Patent ID: 11866396
Assignee: IFP ENERGIES NOUVELLES
Field: Basic materials chemistry (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A process for producing olefins having a number of carbon atoms between 2 and 4 and aromatics by catalytic cracking, comprising the following steps:
contacting some or all of a feedstock comprising naphtha (1), a catalyst (2) and a diluent (3) in a naphtha catalytic cracking reactor (4) to convert at least partly the naphtha-comprising feedstock (1) into olefins having a number of carbon atoms of between 2 and 4 and to produce a cracking effluent (6);
sending the cracking effluent (6) into a first separating section (9) to produce at least the following fractions:
a fraction comprising ethylene (13),
a fraction comprising propylene (14), and
a fraction comprising compounds comprising at least 5 carbon atoms (16), comprising paraffins, olefins and aromatics;

sending at least part of the fraction comprising compounds comprising at least 5 carbon atoms (16) into a second separating section (24) to produce the following fractions:
a fraction comprising compounds comprising 5 carbon atoms (25), which contains less aromatics than fraction (16), and
a fraction comprising compounds comprising at least 6 carbon atoms (26) which is enriched in aromatics in relation to fraction (16);

sending at least part of the fraction comprising compounds comprising at least 6 carbon atoms (26) into an aromatics extraction unit (30) to produce the following fractions:
an aromatics-enriched fraction (31), and
a low-aromatics fraction (32);

recycling at least partly the fraction comprising compounds comprising 5 carbon atoms (25), which achieves the recycling of less aromatics than if the same amount of fraction (16) would have been recycled, and recycling the low-aromatics fraction (32) into the naphtha catalytic cracking reactor (4), which achieves the recycling of less aromatics than if the same amount of fraction (26) would have been recycled; and
sending at least part of the aromatics-enriched fraction (31) into an aromatics separation unit (33) to produce at least the following fractions:
a benzene-rich fraction (34),
a toluene-rich fraction (35),
at least one xylenes-rich fraction (36), and
at least one fraction of aromatics having at least 9 carbon atoms.