Patent ID: 7507325

Claim:
A process for treating a petroleum feedstock for producing at least one gas oil fraction with a sulfur content of at most 50 ppm by weight, wherein at least 80% by weight of the feedstock boils above 340° C. and the feedstock contains at least 0.05% by weight of sulfur, the process comprising: a) mild hydrocracking in a fixed bed of at least one catalyst at a temperature of 330-500° C., a pressure of at least 2 MPa and less than 12 MPa, an hourly space velocity of 0.1 h-1 to 10 h-1 and in the presence of 100-5000 Nm3 of hydrogen/m3 of feedstock, wherein the net conversion of products boiling below 360° C. is 10-50% by weight, b) separating from the effluent of (a) a gas that contains hydrogen, hydrogen sulfide formed in a), a gas-oil containing distillate fraction and a heavier fraction than the gas oil, c) hydrotreating, by contact with at least one catalyst, of said at least one gas-oil containing distillate fraction that is obtained in b) at a temperature of 300-500° C., a pressure of 2-12 MPa, an hourly space velocity of 0.1-10 h-1 and in the presence of 200-5000 Nm3 of hydrogen/m3 of feedstock, and d) separating from the effluent of (c), in a zone different from (b), hydrogen, gases and at least one gas oil fraction with a sulfur content of less than 50 ppm by weight, wherein all of the make-up hydrogen that is necessary to the process is introduced in c).