Abstract: The 3rd RFCCU with a capacity of 2.0 Mt/a in Sinopec Beijing Yanshan Co. ran for more than 1 100 days last operation period. Some issues arose in the flue gas regeneration circuit system at the end of the period. Cracks were found in the lining of the gas flue and local ultra-temperature due to three expansion joints being corroded at the inlet of high temperature heat removal device; the outlet temperature of waste heat boiler was more than 200 ℃(design, 180 ℃) resulting in scaling; One tube bundle exploded and many nicks left; the inlet pipeline of flue gas turbine and the critical nozzle leaked several times. Multiple technical transformations were adopted during the maintenance this year. A large area of linings and five expansion joints were repaired or replaced, material of the inlet pipeline of flue gas turbine was upgraded, and the 4th cyclone separator and a composite phase change heat exchanger were added in the waste heat boiler exit. The operation results reveal that the outlet temperature is reduced to 150 ℃and no ultra-temperature parts in the regeneration flue gas system is observed, resulting in an efficient, economical and long-period operation in RFCCU.