Abstract: A process in which coke is reduced and volatile products yield increased in a catalytic cracking system wherein spent cracking catalyst is stripped in the presence of a hydrogen donor.

Abstract: An apparatus for the fluid catalytic cracking of hydrocarbons having a riser reactor with structure at its lower end for introduction of hydrocarbon feedstock and particulate catalyst and having its upper end opening into a separator vessel. A flow reversal structure attached to a downwardly directed flow reversal conduit is provided at the upper end of the riser and within the separator vessel. The flow reversal structure and conduit serve to direct cracked hydrocarbon products and particulate catalyst downwardly toward a stripper located at the bottom of the separator vessel. Cyclones having gas inlet ducts in communication through the wall of the flow reversal conduit are provided. The cyclones are connected to vent cracked hydrocarbon products outside of the separator vessel.

Abstract: An apparatus for the catalytic cracking of hydrocarbons having two independent transfer line reactors, each of which is associated with an independent cyclone separation system and wherein the cyclone separation systems are located within a common separator vessel. More particularly, the improved apparatus can be used for the simultaneous fluidized catalytic cracking of a hydrocarbon feedstock and the recracking of a selected fraction of the products from said cracking without commingling the feedstock and the selected fraction to be recracked.

Abstract: A method and apparatus for the fluid catalytic cracking of petroleum hydrocarbons wherein an ascending cocurrent stream of vaporous hydrocarbon and entrained catalyst particulates is effected in a tubular reaction zone the method including the following steps: (1) altering the direction of flow of said stream of hydrocarbons and particulates to a downward direction by conducting the stream into a flow reversing zone, (2) accelerating the rate of downward flow of the particulates by gravitational force augmenting fluid flow drag forces to impart momentum thereto, (3) withdrawing cracked hydrocarbons laterally from the downwardly flowing particulates, and (4) contacting the downwardly flowing particulates with inert stripping gas, the momentum of said particulates preventing their passage laterally with the cracked hydrocarbons and permitting their passage counter current to the upward movement of stripping steam.

Abstract: Disclosed is a double-slide valve for controlling a stream of fluid entrained particulate material. The double-slide valve comprises a valve body forming a closed chamber having an inlet opening, an outlet opening, and a pair of valve stem openings. Within the chamber is mounted a flow port having an entrance and an exit opening through which the stream of particulate material passes. The flow of this stream is controlled by two slidable valve plates which slide traversably across the flow port openings upon guide means. The amount of valve plate movement is controlled by a control means.

Abstract: An improvement in a process for catalytic cracking of hydrocarbon feedstocks which comprises reducing the emisssion of catalyst particles through a regenerator effluent gas by passing a catalyst-laden stream from a main column into a slurry settling zone where there is recovered a decanted oil from an upper portion of said zone and an oil (slurry and oil) of catalyst from a bottom portion of said slurry settler. The improvement comprises recycling at least a portion of the decanted oil from said zone to a lower portion of the zone so as to regulate the upward velocity of the oil in said zone to selectively reject through the decanted oil stream small catalyst particles (less than about 20 microns diameter), which if not rejected through the decanted oil stream, would be recycled back to a fluidized catalytic cracking reaction zone in the slurry oil stream and ultimately released to the atmosphere by the effluent gases from the regeneration zone.