Industrial application of blending ethylene cracking heavy oil in delayed coking unit

Ethylene cracking heavy oil is a kind of by-product in the production process of ethylene cracking unit, containing polycyclic aromatic hydrocarbons above double ring and possessing the characteristics of short side chain and high hydrocarbon ratio, and which is often used as fuel oil and the economic benefit is low. In order to improve the utilization value of ethylene cracking heavy oil, the key problem of blending ethylene cracking heavy oil in delayed coking unit was solved. By adding a pretreatment system of ethylene cracking heavy oil and adding stabilizer and peptizer to ethylene cracking heavy oil, the separation and coacervation of ethylene cracking heavy oil mixed with vacuum residue was solved, and the stable blending of ethylene cracking heavy oil in delayed coking unit was realized. The results of industrial application showed that the maximum blending capacity of ethylene cracking heavy oil was 10 t/h, the main operating conditions had no obvious change compared with that before blending, and the yield of gasoline and diesel increased by 2.26%, the yield of coke decreased by 3.36%, and the product properties had little change. When the blending capacity of ethylene cracking heavy oil was kept below 10 t/h, the continuous operation period of the unit could reach more than one year. Since 2017, 106 187 tons of ethylene cracking heavy oil have been blended, achieving economic benefit of RMB 90.259 million yuan.