Abstract: A FCC unit had been operated for a long time without supporting flue gas treatment facilities. The emission concentrations of SO2 and particles from FCC flue gas far exceeded the requirements of specification, resulting in the shutdown of the FCC unit. In order to resume the operation of the unit, new tower internals with ultra-low emission were adopted to ensure that the flue gas is discharged up to the standard. When the pressure drop load of tower internals met the production requirements, the flue gas emission index was far lower than the local environmental protection requirements, and there was no drifting rain or falling rain on the chimney. Good application effect has been achieved.

Key words: FCC unit , ultra-low emission , flue gas treatment , tower internals