Method of converting heavy fractions oil comprising a step of the distillation, the steps in an ebullating bed hydroconversion of the distillate under vacuum and residue under vacuum and a step of catalytic cracking.

摘要

The hydrocarbons are distilled under vacuum, giving a distillate (DSV) and a residue (RSV). Part of the residue is hydrotreated and part is hydroconverted, producing liquids with reduced sulfur and metal content. These are distilled at atmospheric pressure, each giving a residue and a distillate. Part of the residue is treated in the presence of hydrogen in a treatment zone with a 3 phase reactor containing a boiling bed of hydrotreatment catalyst, in conditions which produce a liquid with reduced Conradson Carbon content, metals and sulfur. Part of the residue is treated in the presence of hydrogen in a hydroconversion section containing at least one 3-phase reactor containing at least one boiling bed of hydroconversion catalyst in conditions which produce a liquid with reduced Conradson Carbon content, in metals and sulfur. The hydrotreatment and hydroconversion reactors have upward gas and liquid flow with a catalyst extractor near the base of the reactor and a source of fresh catalyst near the top. The atmospheric distillations occur with an initial boiling point of about 300 deg C, more commonly between 350 and 370 deg C. The two atmospheric residues are mixed and sent to a catalytic cracker to obtain a gaseous fraction, a fuel fraction containing petrol and diesel, and a slurry. Part of the distillate under vacuum is mixed with the residue under vacuum during hydroconversion. The hydrotreatment and hydroconversion are at a pressure of between 2 and 35 MPa absolute and between 300 and 550 deg C, with a spatial duration of 0.1 to 10 per hour. The atmospheric distillations and distillation under vacuum have independent cutoff points of between 300 and 400 deg C, or the atmospheric distillations have the same cutoff between 300 and 400 deg C. Part of the atmospheric residue is returned to the hydroconversion and/or part to the refinery heavy fuel pool.