Preparation of FCC charge from residual fractions

摘要

Residual fractions from distillation of petroleum are rendered suitable for charge to catalytic cracking by high temperature, short time contact in a decarbonizing zone with fluidizable solid particles of essentially inert character and low surface area to deposit high boiling components of the crude and metals on the fluidizable solid particles whereby Conradson Carbon values and metal content of the hydrocarbon feedstock are reduced to levels tolerable in catalytic cracking and carbon laid down on the inert fluidizable particles is burned in a burning zone separate from the decarbonizing zone. Heated inert particles are recycled at least in part to the decarbonizing zone and then to the burning zone. Additional charge of fluidizable inert solid is produced in situ in the burner on a regular or intermittent basis by spraying a slurry of a precursor of the fluidizable inert solid into the hot gases in the burner whereby the sprayed mist dries in the form of fine beads composed of inert material and the beads are cycled to the decarbonizing zone to reduce Conradson Carbon and metals content of new feedstock charge.