Process for refining a hydrocarbon feedstock of the vacuum residue type using selective deasphalting, a hydrotreatment and a conversion of the vacuum residue for production of gasoline and light olefins

Process for refining a heavy feedstock of the vacuum residue type having a boiling point above 400° C., a density greater than 0.96, a content of C7 asphaltenes greater than 4 wt % of C7 asphaltenes relative to the total weight of the feedstock and/or a Conradson carbon content greater than 10 wt % of CCR relative to the total weight of the feedstock, said process comprising the following stages:

• a) a stage of selective deasphalting of the feedstock by a single-stage liquid/liquid extraction in an extractant, said extraction being carried out by means of a mixture of at least one polar solvent and at least one apolar solvent, so as to obtain an asphalt phase and a deasphalted oil (DAO) phase, the proportions of said polar solvent and said apolar solvent in the solvent mixture being adjusted according to the properties of the feedstock, according to the desired yield of asphalt and/or according to the desired quality of the DAO, said deasphalting stage being carried out under the subcritical conditions for the mixture of solvents,
• b) a stage of hydrotreatment of at least a part of the deasphalted oil (DAO) phase originating from stage a) in the presence of hydrogen in at least one fixed-bed reactor containing at least one hydrodemetallization catalyst under conditions allowing an effluent to be obtained with a reduced content of metals and Conradson carbon,
• d) a stage of catalytic cracking of at least a part of the effluent originating from stage b) in at least one fluidized-bed reactor under conditions allowing a gasoline fraction and/or a light olefins fraction to be produced.