Process for the production of middle distillate from a conventional heavy feedstock including a step for selective hydrogenation of the ex FCC HCO cut

摘要

The present invention describes a process for the conversion of a heavy feedstock for improving the production and selectivity for middle distillate, said process using a catalytic cracking unit followed by a unit for selective hydrogenation of the heavy distillate cut (HCO) or any other cut rich in triaromatic compounds before recycling it to the FCC reaction zone in order to maximize the middle distillate cut.

主权项

1. A process for converting a heavy hydrocarbon feedstock having improved selectivity for middle distillate (LCO) with a distillation range in the range 220° C. to 360° C. comprising:
cracking a feedstock using a catalytic cracking unit (FCC) to obtain a heavy distillate cut (HCO), wherein said (HCO) comprises triaromatics in an amount of more than 60% by weight, and has a distillation range of 320° C. to 490° C., selectively hydrogenating said HCO with at least one selective hydrogenation unit, reintroducing said HCO cut into a reaction zone of the FCC unit, wherein the at least one selective hydrogenation unit is operated at a pressure of 15 to 50 bar, and at a temperature of 325° C. to 360° C. and in the presence of a hydrotreatment catalyst comprising 1% to 10% by weight of nickel, associated with 1% to 30% by weight of molybdenum, on an alumina support; and wherein the catalytic cracking unit (FCC) comprises: two distinct upflow reactors comprising a first processing of the heavy hydrocarbon feedstock under the following conditions: reactor outlet temperature (ROT1) in the range 450° C. to 650° C., and a C/O ratio in the range 2 to 20 and a second processing of the hydrotreated heavy distillate cut (HCO) under the following conditions: reactor outlet temperature (ROT2) in the range 500° C. to 600° C., a C/O ratio in the range 2 to 20 and, wherein the process results in a lower concentration of LPG than HCO.