Abstract: The fluid catalytic cracking (FCC) unit is a core unit in petrochemical production. The stable operation of its reactor-regenerator (R-R) system directly determines the overall production efficiency and economic benefits of the entire unit. During operation, the reactor-regenerator system utilizes cyclone separators to achieve efficient separation of the catalyst from the process gas, thereby preserving catalyst activity and maintaining the pressure balance across the R-R system. As the key equipment in this process, the long-term operation capability of cyclone separators significantly affects the stability and efficiency of the FCC unit. In actual operation, cyclone separators often experience a reduction in separation efficiency due to issues such as equipment wear, blockage, deformation and failure, which lead to a decline in separation efficiency and consequently constrain the long-term safe operation of the unit. To address these issues, this paper systematically analyzes the major bottlenecks encountered during the long-term operation of cyclone separators, and proposes targeted optimization and improvement measures. The aim is to provide theoretical reference and practical guidance for enhancing the operational performance of the reactor-regenerator system in fluid catalytic cracking units.

Key words: cyclone separator, separation efficiency, wear, structural optimization