Process and apparatus for regeneration of fcc catalyst with reduced nox

Abstract

A process and apparatus for increasing the coke burning capacity of FCC catalyst regenerators is disclosed. An auxiliary regenerator receives spent catalyst from an FCC stripper and burns some of the coke at turbulent or fast fluidized bed conditions. Partially regenerated catalyst and flue gas enter a low pressure drop cyclone discharging more than 90% of the partially regenerated catalyst down into a bubbling or fast fluidized bed in the primary regenerator. Flue gas from the auxiliary regenerator is discharged into the dilute phase above the bed in the primary regenerator. Catalyst entrainment from the fluidized bed in the primary regenerator may be reduced because less combustion air is needed as a result of partial regeneration in the auxiliary regenerator. Reduced NOx and dust emissions, and/or increased coke burning capacity, may be achieved, especially when a bubbling dense bed primary catalyst regenerator is used.