Process for thermally cracking heavy hydrocarbon oil

Claim 1

A process for continuously thermally cracking a heavy hydrocarbon oil, comprising the steps of: (a) feeding the heavy hydrocarbon oil into a first thermal cracking zone for thermally cracking the heavy hydrocarbon oil and for obtaining a first, thermally cracked product; (b) introducing the first product into a second thermal cracking zone to which a gaseous heat transfer medium is supplied for direct contact with the liquid phase in the second thermal cracking zone, including the first product, so that the first product is further thermally cracked to form a second, thermally cracked product including distillable cracked components and a mesophase-containing pitch forming a part of the liquid phase, said distillable cracked components being stripped with the gaseous heat transfer medium from the liquid phase; (c) discharging said liquid phase from the second thermal cracking zone and introducing same into a first separating zone for separating the liquid phase into a mesophase rich pitch having a higher concentration of mesophase than the liquid phase and a matrix pitch having a lower concentration of mesophase than the liquid phase; (d) recycling at least a part of said matrix pitch to said second thermal cracking zone; (e) removing said stripped, distillable cracked components overhead from said second cracking zone and introducing same into a second separating zone for separating same into a light fraction and a heavy fraction; (f) introducing at least a part of said heavy fraction into a third thermal cracking zone for thermally cracking same and for obtaining a third, thermally cracked product including light oil components and an aromatic tar; and (g) recycling the aromatic tar to said second cracking zone.