关键词: 渣油, 弹丸焦, 沥青质, 胶质

Abstract: Shot coke was formed in delayed coking unit when processing poor quality crude oils. By reviewing coke formation mechanism and analyzing the properties of residue feedstock which shot coke was formed, it was found that high in asphaltene and metals (Ni+V) contents of feedstock was the main cause of shot coke formation. Measures, such as proper adjusting the blending ratios of various residue feeds to control the feedstock properties including asphaltene content, metals content and stable factor not more than 9.3%, 244 μg/g and 0.30, respectively, could significantly reduce the chance of forming shot coke. Furthermore, when processing poor quality residue feedstock, optimizing operation parameters, such as decreasing furnace outlet temperature, increasing recycle ratio and reaction pressure, could suppress the formation of shot coke as well.

Key words: petroleum residue, shot coke, asphaltene, resin