DCC装置再生斜管流化不稳定原因分析

Analysis of the causes of instability ofthe regeneration inclined pipe fluidization in the DCC unit

结合流化基本理论和装置运行情况,对中海石油宁波大榭石化有限公司2.2 Mt/a催化裂解(DCC)装置再生斜管流化不稳定,导致反应温度波动大、斜管振动大的问题进行了分析,认为斜管流化不稳定的主要原因是斜管入口携带气体量过多和斜管松动点设置不合理导致催化剂在斜管内呈现鼓泡床流化。通过对脱气罐进行改造、提高再生器床层藏量、降低脱气罐氮气量、优化斜管松动点布置、控制平衡催化剂中细粉含量等措施,提高了脱气罐脱气效果,降低了斜管催化剂携带气量,再生斜管流化得到了明显改善,反应温度最大波动幅度由±5℃降至±2℃,再生斜管振幅由5~6 mm降至1~2 mm,为装置高效长周期运行提供了基本保障。

Combined with the basic theory of fluidization and the operation of the unit,the problems of unstable fluidization of the regeneration inclined pipe of the 2.2 MM TPY DCC unit of CNOOC Ningbo Daxie Petrochemical Co.,Ltd.,which resulted in large fluctuation of reaction temperature and large vibration of the inclined pipe,were analyzed.It was believed that the main reasons for the instability of fluidization in inclined pipe were the excessive gas carried at the inlet of the inclined pipe and the unreasonable setting of the loosening point of the inclined pipe.The catalyst exhibits bubbling bed fluidization inside the inclined pipe.By modifying the degassing tank,improving the reservoir volume of the regenerator bed,reducing the nitrogen volume of the degassing tank,optimizing the setting of the loosening point,controlling the fine powder content in the equilibrated catalyst,the degassing effect of the degassing tank was improved,the catalyst carrying gas volume in the inclined pipe was decreased,and the fluidization of the regeneration inclined pipe was significantly improved.The maximum fluctuation amplitude of the reaction temperature is reduced from±5℃to±2℃,and the amplitude of the regeneration inclined pipe is reduced from 5~6 mm to 1~2 mm,providing basic guarantees for the efficient long cycle operation of the unit.