process for cracking catali tico fluidized to produce naphtha and gas oil recycle

摘要

1455839 Cracking TEXACO DEVELOPMENT CORP 7 Dec 1973 [2 Jan 1973] 56808/73 Heading C5E In a fluidized catalytic cracking process, a waxy hydrocarbon charge stock is separated into a light fraction boiling in the range 400-650‹ F. and having a pour point greater than 10‹ F., and a heavy fraction boiling above 650‹ F., the two fractions are cracked in separate risers. catalyst and hydrocarbon vapours from both risers are discharged into a common disengaging space and the vapours from the disengaging space fractionated into at least four fractions: C 4 and lighter, naphtha, light gas oil boiling in the range 400-650‹ F. and one or more heavier fractions. The cracking of the light fraction is at 950‹ to 1100‹ F. and at a conversion of at least 80%, to maintain the pour point of the light gas oil product at 10‹ F. or less, while the cracking of the heavy fraction is at 900‹ to 1050‹ F. and a conversion of 60 to 85%. This enables the ratio of naphtha to light cycle gas oil to be varied with seasonal variations in demand by varying the conversion of the heavy fraction, while keeping the pour point of the light cycle gas oil low enough for use as a furnace oil. Reference has been directed by the Comptroller to Specification 1,167,254.