Patent ID: 7704377

Claim:
A process for treating a heavy petroleum feedstock, of which 80% by weight has a boiling point of greater than 340° C., said process comprising: (a) hydroconversion in a boiling-bed reactor operating with a rising flow of liquid and gas at a temperature of between 300 and 500° C., a liquid hourly space velocity relative to the catalyst volume of from 0.1 to 10 h −1 and, in the presence of 50 to 5000 Nm 3 of hydrogen per m 3 of feedstock, conversion in % by weight of the fraction having a boiling point of greater than 540° C. being from 10 to 98% by weight, whereby a hydroconversion effluent is produced; (b) separation of hydroconversion effluent obtained from (a) into a gas containing hydrogen and H 2 S, a fraction comprising gas oil, a naphtha fraction, and optionally a fraction that is heavier than the gas oil; c) hydrotreatment, by contact with at least one catalyst, of at least said fraction comprising gas oil obtained from (b) at a temperature of from 200 to 500° C., at a liquid hourly space velocity relative to the catalyst volume of 0.1 to 10 h −1 , and in the presence of 100 to 5000 Nm 3 of hydrogen per m 3 of feedstock, whereby a hydrotreatment effluent is produced; and d) separation of hydrotreatment effluent obtained from (c) into a gas containing hydrogen and at least one gas oil fraction having a sulfur content of less than 50 ppm, wherein the hydroconversion in (a) is conducted at a pressure P 1 and the hydrotreatment in (c) is conducted at a pressure P 2 , and the difference ΔP=P 1 −P 2 is at least 3 MPa, and hydrogen supply for the hydroconversion in (a) and hydrotreatment in (c) is delivered by a single compression system with n stages, n being greater than or equal to 2.