Causes Leading to Formation of Shot Cokes and Measures for Its Prevention in Super Viscous Oil Delay

• 作 者: Chen Chunmao Zhang Feng Yan Guangxu Guo Shaohui
• 机 构: State Key Laboratory for Heavy Oil Processing,China University of Petroleum,Beijing 102249;Liaohe Pe
• 出 处: 中国炼油与石油化工（英文版）
• 发表日期: 2007年1期
• 关键词: delayed coking unit super viscous oil shot cokes preventive methods

Shot cokes are frequently formed in the delayed coking unit treating the super viscous oil at PetroChina’s Liaohe Petrochemical Company. Considerable work has been carried out to avoid the formation of shot cokes. The test results obtained have shown that the property of super viscous oil has played a key role in the formation of shot cokes. After adjusting and optimizing the process indices the operating regime of the delayed coking unit at a throughput of 118t/h of the super viscous oil is specified as follows: a reaction temperature of 498-502℃, a reaction pressure of 0.17-0.25 MPa, a recycle ratio of 0.5-0.6 and a fractionation tower bottom temperature of 355-365 ℃. In the meantime,the delayed coking process has adopted measures to enhance pre-fractionation of the feedstock to rationally remove light fractions and maintain a steady gas velocity in order to avoid the formation of shot cokes.