Process for the preparation of olefins, comprising hydrotreatment, de-asphalting, hydrocracking and steam cracking

A process for producing olefins from a hydrocarbon feedstock (1) with a sulfur content of at least 0.1 weight %, an initial boiling point of at least 180° C. and a final boiling point of at least 600° C., said process comprising:

• a) a hydroconversion step performed in an ebullated-bed reactor, in which said heavy hydrocarbon feedstock (1) is contacted, in the presence of hydrogen (2), with a hydroconversion catalyst, said step enabling production of an effluent (3);
• b) a step of separation of the effluent (3) obtained from hydroconversion step a) into a gaseous fraction (4), a fraction (11) comprising compounds with a boiling point of between 350 and 540° C., and a liquid vacuum residue fraction (5) comprising compounds with a boiling point of at least 540° C.,
• c) a deasphalting step by liquid-liquid extraction of the vacuum residue fraction (5) obtained from separation step b), step c) being implemented by means of a solvent (6) or a mixture of solvents, enabling production of an asphalt-comprising fraction (7) and a deasphalted oil fraction (8),
• d) a step of extraction of aromatics from at least part of the deasphalted oil fraction (8) obtained from deasphalting step c), and from at least part of the fraction (11) obtained from separation step b), enabling production of an extract fraction (13) and a raffinate fraction (10),
• e) a step of fixed-bed hydrocracking of at least part of the extract fraction (13) obtained from step d) in the presence of hydrogen (12) and a hydrocracking catalyst, enabling production of hydrocracking effluent (14),
• f) a step of separation of the hydrocracking effluent (14) obtained from the fixed-bed hydrocracking step e) into at least one hydrocracked gaseous fraction (15) and at least one hydrocracked liquid fraction (16),
• g) a step of steam cracking of the raffinate fraction (10) obtained from extraction step d) and of the hydrocracked liquid fraction (16) obtained from separation step f), including compounds with a boiling point of less than 350° C., enabling production of a steam-cracked effluent (17),
• h) a step of separation of the steam-cracked effluent (17) obtained from the steam cracking step g), enabling production of at least one hydrogen-comprising fraction (18), an ethylene-comprising fraction (19), a propylene-comprising fraction (20), and a fraction (21) comprising pyrolysis oil.