Continuous process for treating a hydrocarbon-containing feedstock containing at least one hydrocarbon-containing fraction having a sulphur content of at least 0.1% by weight, an initial boiling temperature of at least 340° C. and a final boiling temperature of at least 440° C., the process comprising the following stages:
- a) a hydrodemetallization stage in which at least two permutable reactors are utilized at a temperature comprised between 300° C. and 500° C., and under an absolute pressure comprised between 5 MPa and 35 MPa, in the presence of the hydrocarbon-containing feedstock and hydrogen, and of a hydrodemetallization catalyst;
- by “permutable reactors” is meant a set of at least two reactors, one reactor of which can be stopped, generally for regeneration or replacement of the catalyst or for maintenance, while the other (or others) is (are) operating,
- b) a fixed-bed hydrotreatment stage comprising at least one reactor in which the effluent originating from stage a) when this exists, or the hydrocarbon-containing feedstock directly when stage a) does not exist, is brought into contact with at least one hydrotreatment catalyst at a temperature comprised between 300° C. et 500° C. and under an absolute pressure comprised between 5 MPa et 35 MPa,
- c) a fixed-bed hydrocracking stage in which at least two permutable reactors are implemented at a temperature comprised between 340° C. and 480° C., and under an absolute pressure comprised between 5 MPa and 35 MPa, in the presence of the effluent originating from stage b), and a hydrocracking catalyst,
- d) a stage of separation of the effluent originating from stage c), in order to obtain at least one gaseous fraction and at least one heavy liquid fraction,
- e) a stage of precipitation of the sediments contained in the heavy liquid fraction originating from stage d) which can be carried out according to 3 possible variants called destabilization (e1), oxidation (e2), or oxidizing destabilization (e3), the operating conditions common to the three variants being the following:
- residence time less than 60 minutes,
- temperature between 80 and 250° C.,
- pressure less than 1.5 MPa,
- f) a stage of physical separation of the sediments of the heavy liquid fraction originating from stage e) of precipitation in order to obtain a fraction containing the sediments, and a liquid hydrocarbon-containing fraction having a reduced sediment content,
- g) a stage of recovery of a liquid hydrocarbon-containing fraction having a sediment content after ageing of less than or equal to 0.1% by weight consisting of separating the liquid hydrocarbon-containing fraction having a reduced sediment content originating from stage f) from the distillate cut introduced during stage e) and which is recycled to said stage e).