CATALYTIC CRACKING OF NAPHTHA AND GAS OIL

Low octane naphtha and fresh gas oil are catalytically cracked with a zeolite catalytic cracking catalyst in separate elongated reaction zones yielding a naphtha having an increased octane rating. Recovering a naphtha fraction, particularly a heavy naphtha fraction, from the cracked product, and combining it with the fresh naphtha feed, further enhances the octane rating of the naphtha product. A cycle gas oil may be recovered from the reactor effluent and combined with the fresh naphtha feed or introduced into a separate (a third) elongated reaction zone to effect maximum recovery of naphtha and lighter stocks having improved product quality. Optionally, any of the feedstocks may be subjected to further cracking in a dense bed of the zeolite catalyst.