Quality of slurry oil recycle in fluid catalytic cracking

Claim 1

A PROCESS FOR THE FLUID CATALYTIC CRACKING OF PETROLEUM HYDROCARBONS COMPRISING PASSING A PETROLEUM HYDROCARBON CHARGE STOCK THROUGH A FLUID BED OF A CRACKING CATALYST IN A REACTOR AT CRACKING CONDITIONS, DISCHARGING REACTION PRODUCTS AND ENTRAINED CATALYST FROM THE REACTOR, CONDENSING A HEAVY HIGH BOILING FRACTION OF REACTION PRODUCTS AND COLLECTING ENTRAINED CATALYST THEREIN, EXTRACTING AROMATIC FRACTIONS FROM THE HEAVY HIGH BOILING FRACTION WITH A SOLVENT HAVING A SPECIFIC GRAVITY LOWER THAN THE SPECIFIC GRAVITY OF THE HEAVY HIGH BOILING FRACTION AND A PREFERENTIAL SOLUBILITY FOR AROMATIC HYDROCARBONS, SEPARATING A RAFFINATE AND ENTRAINED CATALYST FROM THE EXTRACT, AND RECYCLING THE RAFFINATE AND ENTRAINED CATALYST TO THE REACTOR.