Abstract: In a two stage catalytic cracking process a heavy cycle gas oil fraction (HCGO) nominal boiling range 600.degree. F. to 1050.degree. F., API gravity of -10.degree. to +10.degree. and 65 to 95 vol % aromatics is recycled to extinction between an ebullated bed hydrocracking zone and fluidized catalytic cracking zone to yield a liquid fuel and lighter boiling range fraction as the light fraction from each zone.The catalyst in the fluidized catalytic cracking zone is maintained at a micro activity 68 to 72 while cracking a virgin gas oil to HCGO. HCGO is then mixed with vacuum residuum and hydrocracked in an ebullated bed reactor. The mid range fraction is recycled to the fluidized catalytic cracking zone. The 1000.degree. F..sup.+ fraction is blended with a fuel oil.

Abstract: A mixture of hydrocarbons consisting of gas oil and residual oil is catalytically cracked in the presence of a fluidized zeolite catalyst. The mixture of hydrocarbons is classified by boiling range as a 550.degree.-1000.degree. F. gas oil and a 1000+.degree. F. vacuum residuum. The gas oil is selectively cracked using a freshly regenerated fluid zeolite catalyst having less than 0.1 wt % residual carbon to give a high yield of desirable liquid hydrocarbon boiling from about 60.degree.-670.degree. F. The vacuum residuum is injected into the riser reactor at a point near the riser outlet to quench the cracking reactions in the gas oil. The vacuum residuum undergoes a small amount of reaction removing undesirable materials and yielding a liquid hydrocarbon boiling up to about 1000.degree. F. The amount of vacuum residuum cracking and overall yield of liquid hydrocarbons are controlled by downstream injection of vacuum residuum into the riser.

Abstract: A two-stage cascade flow fluid catalytic cracking process capable of converting high molecular weight hydrocarbons containing catalyst poisons into products of lower molecular weight with high activity cracking catalyst susceptible to catalyst poisons, the cascade flow process resulting in higher yields of desired motor fuel fractions than those obtainable with conventional riser flow fluid catalytic cracking processes. Catalyst poisons, e.g.

Abstract: A process for the production of highly aromatic petroleum fractions from various petroleum feedstocks suitable for catalytic cracking in a fluidized catalytic cracking unit wherein heavy gas oil from a first fluidized catalytic cracking unit is subjected to further catalytic cracking in a separate fluid catalytic cracking unit at temperatures in the range of 565.degree. to 650.degree. C. producing light olefins and a heavy gas oil consisting of essentially aromatic components suitable for the production of needle coke, and the method of producing needle coke from various hydrocarbon cracking stocks.

Abstract: The hydrogen consumption in the catalytic desulfurization of hydrocarbon oils is reduced by the incorporation in the catalyst of a small amount of arsenic.