Abstract: In view of the current situation of the decreasing demand for diesel and the difficulty of diesel products leaving the factory, combined with the advantages of integrated refining and chemical unit, three processes, hydrofining, single-stage hydrocracking (SSOT) and adsorption dearomatization, were used to carry out the diesel pretreatment. The pyrolysis performance of three pretreated products was evaluated by the test equipment, and the coking performance of the products was also investigated. The results showed that the pyrolysis performance of diesel pretreated by SSOT and adsorption dearomatization process was significantly improved, which could be used as steam cracking feedstock, and adsorption dearomatization process had higher aromatics removal rate than the SSOT process. The yield of target olefin of the low aromatics fraction was significantly increased,while the yield of coke was remarkablely decreased. Optimization of pyrolysis furnace outlet temperature (COT) of low aromatics fraction after adsorption dearomatization pretreatment was carried out on a test set. The results of coking performance optimization test showed that, when the adsorption dearomatization low aromatic fraction was used as steam cracking raw material, the recommended COT was 830 ℃, and the recommended sulfide addition content was 200-300 μg/g.

Key words: diesel, adsorption, dearomatization, steam cracking, ethylene, propylene