Why is integrated refining-petrochemical scale critical for cracking C9 deep processing?

Why is integrated refining-petrochemical scale critical for cracking C9 deep processing?
Cracking C9 economics hinge on scale. Even a 1.4 million tonne ethylene steam cracker yields only 100,000-200,000 tonnes of C5/C9 byproducts, while traditional small refineries produce roughly 10,000 tonnes, far below the threshold for viable deep processing. Most plants therefore sell the fraction as raw material. Integrated giants change this: one major Zhejiang complex generates over 400,000 tonnes each of cracking C5 and C9 annually, enough to justify dedicated downstream units producing piperylene resin, DCPD resin, and cold-polymerized C9 resin. This integration captures value that standalone crackers cannot, and it explains why new mega-refineries are building C5/C9 utilization into their original designs rather than treating the stream as fuel.