Process for the conversion of heavy petroleum fractions for the production of a feedstock for a catalytic cracking process and low sulfur middle distillates

摘要

Treatment of a charge of which at least 80% has a boiling point above 340 degrees C and contains at least 0.05% sulfur, to produce a gasoil of sulfur content less than 50 ppm by a 4 stage process involving mild hydrocracking, separation of gases form the effluent formed, hydrotreatment and separation of hydrogen with production of a gasoil of less than 50 ppm of sulfur. The process comprises: (a) mild hydrocracking in a catalytic fixed bed at 330-500 degrees C, 2-12 MPa, VVH of 0.1-10 h<-1> and in the presence of 100-5000 Nm<3> of H2/m<3> of charge, the net conversion to products boiling below 360 degrees C being 10-50 wt.%; (b) the separation from the effluent of a gas containing H2, H2S and a fraction heavier than the gasoil; (c) hydrotreatment by contact with a catalyst of a distillate cut obtained in (b) which includes a gasoil fraction at 300-500 degrees C, 2-12 MPa, a VVH of 0.1-10 h<-1> and in the presence of 200-5000 Nm<3> of H2/m<3> of charge; and (d) the separation of H2, gases and a gasoil of S content less than 50 ppm weight. An Independent claim is also included for the apparatus used for the above process.