On-site solvent generation and makeup for tar solvation in an olefin plant

A process for generating on-site a C6+C7 aromatic rich solvent stream, the process comprising:

• directing a hydrocarbon stream from a last compartment of a quench water separator drum to a primary fuel oil separation tower;
• separating C6+C7 aromatic hydrocarbons from C8+ hydrocarbons in the primary fuel oil separation tower to form a C6+C7 aromatic rich solvent overhead stream and a C8+ hydrocarbon bottoms stream;
• recycling the C6+C7 aromatic rich solvent overhead stream to a feed stream of the quench water separator drum in an effective amount to separate tar from a water phase in the quench water separator drum and dissolve the tar in a hydrocarbon phase of the quench water separator drum;
• and
• mixing the hydrocarbon stream from the last compartment of the quench water separator drum with a portion of a C6+C7 rich bottoms stream from a debutanizer prior to entering the primary fuel oil separation tower thereby increasing the amount of C6+C7 aromatic hydrocarbons in the C6+C7 aromatic rich solvent overhead stream.