Abstract: The hydrochloric acid has been used to reactivate the Ni, Fe-deposited fluid cracking catalyst. The results show that the HCl treatment can partly remove the nickel and the iron deposited on the catalyst and regenerate its activity, increasing the gasoline yield and decreasing the carbon deposit.The hydrothermal stability of the catalyst is not affected by the HCl treatment.

Key words: residual oil, catalytic cracking, regeneration