Patent ID: 7718050

Claim:
A process for treatment of a total hydrocarbon feedstock in which: a gas oil fraction and an atmospheric residue are drawn off by atmospheric distillation of a crude oil, a vacuum distillate that is sent into mild hydrocracking is drawn off by vacuum distillation of said atmospheric residue, said vacuum distillate, as a primary feedstock is such that at least 85% by weight of said primary feedstock boils above 375° C. and at least 95% by weight of said primary feedstock boils below 650° C., is treated by mild hydrocracking in the presence of hydrogen and a catalyst, whereby the mild hydrocracking is performed under an absolute pressure of 2 to 12 MPa and a temperature of between 300 and 500° C., and in the presence of a lighter hydrocarbon fraction, a so-called secondary feedstock, consisting essentially of a gas oil fraction for which the temperature T 5 is between 190 and 210° C. and the temperature T 95 is between 380 and 420° C., to achieve a net conversion of products boiling below 375° C. of 5 to 50% b.w., the effluent that is obtained from the mild hydrocracking is separated to provide a fraction that has an initial boiling point of more than 320° C., and containing less than 0.25% by weight of sulfur, —and a gas oil fraction whose distillation range is between 130 and 390° C., having a D 15 : 0.845-0.855, sulfur content: 5-200 ppm by weight, cetane number: 48-52, said fraction that has an initial boiling point of more than 320° C. is sent into a catalytic cracking section to obtain an LCO and an HCO.