Process for conversion of feedstocks obtained from renewable sources based on marine fuels

Process for the production of diesel fuel bases comprising a sulfur content of less than 100 ppm, starting from a feedstock that is obtained from a renewable source, comprising the following stages:

• a) A stage for bringing the feedstock into contact with a fixed-bed hydrotreatment catalyst, at a temperature of between 200 and 450° C., at a pressure of between 1 MPa and 10 MPa, at an hourly volumetric flow rate of between 0.1 h−1 and 10 h−1 and in the presence of a total quantity of hydrogen mixed with the feedstock such that the hydrogen/feedstock ratio is between 150 and 750 Nm3 of hydrogen/m3 of feedstock for producing an effluent that comprises a gaseous fraction comprising hydrogen and a hydrocarbon-based liquid fraction,
• b) A stage where at least a portion of the effluent that is obtained from stage a) is subjected to separation into a gaseous fraction comprising hydrogen and a hydrocarbon-based liquid fraction,
• c) A stage where at least a portion of the separated hydrocarbon-based liquid fraction obtained from stage b) is subjected to elimination of hydrogen sulfide dissolved in said hydrocarbon-based liquid fraction before stage d),
• d) A stage for bringing into contact at least one portion of the hydrocarbon-based liquid fraction in the presence of a selective hydroisomerization catalyst in a fixed bed, said catalyst comprising at least one group VIII metal and/or at least group VIB metal, said stage d) being carried out at a temperature of between 300 and 380° C., at a pressure of between 3 MPa and 7 MPa, at an hourly volumetric flow rate of between 0.5 and 5 h−1, and in the presence of a total quantity of hydrogen mixed with said hydrocarbon-based liquid fraction such that the hydrogen/hydrocarbon-based liquid fraction ratio is between 70 and 1,000 Nm3/m3,
• e) A stage for separating the effluent that is obtained from stage d) into a gaseous fraction that comprises hydrogen and at least one diesel-fuel-based fraction,
• and in which the hydrogen that is used in stage a) and/or in stage d) is obtained at least in part from the separated gaseous fraction of stage e) and in part from the separated gaseous fraction of stage b).