Process for the hydroconversion of heavy hydrocarbon oils with reduced hydrogen consumption operating at full conversion

A process for the hydroconversion of heavy hydrocarbon oils, said process comprising the following steps:

• a) introducing at a lower portion of a reactor (1), of H meters in height:
• a heavy hydrocarbon oil feedstock consisting of, or comprising, a residue T ° C.+,
• “residue T ° C.+” meaning a vacuum residue having, at atmospheric pressure, the initial boiling point at T ° C.,
• said feedstock being introduced into said reactor (1) at a flow rate corresponding to an hourly space velocity Vs,
• “hourly space velocity Vs at which said feedstock is introduced into said reactor (1)” meaning the ratio of the flow rate, expressed in m3/h, at which said feedstock is introduced into said reactor (1), to the volume of said reactor (1), expressed in m3;
• a gas including hydrogen;
• an hydroconversion slurry catalyst comprising compounds of one or more transition metals,
• said reactor (1) operating at a temperature higher than 340° C. and at a pressure between 50 bars and 250 bars,
• a reaction mixture including a liquid phase, corresponding to a reaction liquid, and a gaseous phase generating in said reactor (1);
• b) withdrawing said reaction mixture from said reactor (1), at an upper portion thereof, and separating said gaseous phase from said liquid phase for recovering hydroconversion products, in the gas state and in the vapor state, and unreacted hydrogen, wherein,
• said separation of said gaseous phase from said liquid phase takes place by introducing said reaction mixture withdrawn from said reactor (1) into a phase separator (7),
• at least one maltenic hydrocarbon fraction being introduced into said phase separator (7) at a lower portion thereof, so as to be added to said liquid phase,
• “maltenic hydrocarbon fraction” meaning an hydrocarbon fraction soluble in n-heptane,
• said maltenic hydrocarbon fraction being introduced into said separator (7) at a flow rate such that in the liquid mixture resulting from the addition of said maltenic hydrocarbon fraction to said liquid phase, the ratio of the weight percentage of maltenes to the weight percentage of asphaltenes is greater than two;
• c) subjecting said liquid phase separated from said gaseous phase to distillation with final stage under vacuum, for extracting high boiling hydroconversion products;
• d) introducing into said reactor (1), at said lower portion, a vacuum residue of said final vacuum stage distillation,
• wherein:
• at step d), said vacuum residue is introduced into said reactor (1) at a unit flow rate greater than Vs×H,
• “unit flow rate at which said vacuum residue is introduced into said reactor (1)” meaning the ratio of the flow rate, expressed in m3/h, at which said vacuum residue is introduced into said reactor (1), to the section of said reactor (1), expressed in m2.