Abstract: Fluid catalytic cracking (FCC) catalysts are poisoned and deactivated due to metal deposition during operation. Traditional landfill treatment not only causes ecological pollution, but also increases production costs. Therefore, finding an effective regeneration method has become a hot issue in the industry. Dithiocarbamates (DTC-CTS) was synthesized by modified chitosan made by nucleophilic addition reaction using chitosan and CS2 as raw materials. The DTC-CTS was used to remove vanadium from spent FCC catalyst to achieve the purpose of regeneration. The technological conditions of vanadium removal using DTC-CTS were further investigated. It was found that at 125℃ and the reaction time of 4.5h, the vanadium removal ratio reached the maximum (54.9%), which indicates that DTC-CTS has a good removal efficiency on vanadium from the equilibrium catalyst. The structure of FCC equilibrium catalyst before and after regeneration was determined by XRD、BET and SEM techniques. The results showed that the crystal structure of Y zeolite was retained in the regenerated catalyst, and the specific surface area and pore volume of the catalyst were increased. The MAT activity was increased by 5 percentage points.

Key words: modified chitosan, vanadium removal, catalytic cracking, equilibrium catalyst regeneration