摘要
The properties and structural changes of unconverted oil(UCO)obtained from ebullated bed hydrogenation at different residue conversion rates were analyzed to clarify the reaction process of heavy components.Meanwhile,the processing routes of UCO,delayed coking,and solvent deasphalting,were investigated.The results showed that with the increase of conversion,the impurity removal rate increased;meanwhile the contents of sulfur and metal in UCO decreased,while the contents of nitrogen and residual carbon increased,and the colloidal stability of UCO became worse.The structural parameters of UCO indicated that the change in molecular structure of heavy oil mainly covered the opening of cycloalkanes ring,hydrogenation saturation of aromatic rings and dealkylation reaction during hydrogenation in the ebullated bed;the aromatic structure was basically unchanged at high conversion,and was mainly due to the ring opening of cycloalkanes and the fracture reaction of alkyl side chains.The coking route of UCO showed that low sulfur petroleum coke with different grades could be prepared by adjusting the conversion in ebullated bed to produce UCOs with different properties.The coke generating coefficient and sulfur transfer coefficient in UCO coking process were higher than those in residue coking.The properties of deasphalted oil(DAO)of UCO were significantly improved and could be used as FCC or hydrocracking feedstock.The DAO yield of UCO feedstock at high conversion was higher,and its sulfur content was lower and CCR value was higher.
