Process for converting petroleum fractions, comprising an ebullated bed hydroconversion step, a separation step, a hydrodesulphurisation step and a cracking step

摘要

A process for converting a hydrocarbon fraction comprises a step a) for treating a hydrocarbon feed in the presence of hydrogen in at least one three-phase reactor (1), containing at least one ebullated bed hydroconversion catalyst, a step b) in which at least a portion of the effluent from step a) is sent to a separation zone (2) from which a fraction F1 normally containing at least a portion of the gas, gasoline and atmospheric gas oil contained in the effluent from step a) is recovered, and a fraction F2 is recovered normally principally containing compounds with boiling points of more than that of the atmospheric gas oil, a step c) for hydrodesulphurization of at least a portion of fraction F1 in at least on reactor (4) containing at least one fixed bed hydrotreatment catalyst under conditions for producing an effluent with a reduced sulphur content, and a step d) in which at least a portion of fraction F2 is sent to a catalytic cracking section (6).