Abstract: An apparatus for the fluidized catalytic cracking of hydrocarbon feedstocks. The apparatus accomplishes the separate and simultaneous contacting of two fluid streams, at least one of which is a hydrocarbon feedstock, with cracking catalyst followed by the removal of the vaporous products therefrom with minimal commingling. The apparatus comprises multiple riser reactors, a partition positioned in the disengaging vessel separating the dilute phase into two regions, and a control system for controlling the direction and volume of flow between the two dilute phase regions at a desired point. The apparatus is particularly suitable for use in the simultaneous fluidized catalytic cracking of dissimilar hydrocarbon feedstocks with minimal commingling of the products therefrom.

Abstract: In a fluidized cracking unit, the cracking catalyst regeneration vessel is specially adapted for high temperature operation to permit essentially complete combustion of coke on the spent catalyst particles and, in addition, the essentially complete combustion of carbon monoxide produced thereby, within the dense phase zone of the regenerator. A partition in the regenerator divides the lower dense phase zone operating at high temperatures from the upper dilute phase zone which may be cooled, for instance, by boiler tubes, water sprays and the like. The partition contains one or more rough separation catalyst knock-out means such as cyclone separators whereby hot catalyst particles are separated from the rising combusted cases and returned to the dense phase regeneration zone. In one embodiment, the regeneration vessel is elongated to facilitate recovery of most of the extra heat produced by complete carbon monoxide combustion by the catalyst particles returning to the dense phase zone.

Abstract: Flue gas containing CO.sub.2 and CO from a fluidized cracking unit catalyst regenerator is fed to a combustor in which CO combustion is completed. The CO combustion can be enhanced by injection of air or oxygen-containing gas into the combustor. The combustor may include CO combustion promoters such as oxidation-promoting catalyst grids, and may also include auxiliary fuel injection or other means to initiate or facilitate the combustion. The process of this invention further comprises indirect or direct recovery of the heat resulting from the combustion of CO in the flue gas by the cracking catalyst particles, which may be returned separately to the regenerator bed or transferred to the cracking reactor with or without fresh catalyst, or may be recycled to the CO combustor inlet or combined with other catalyst particles passing to the regenerator.

Abstract: In a fluidized cracking unit, the cracking catalyst regeneration vessel is specially adapted for high temperature operation to permit essentially complete combustion of coke on the spent catalyst particles and, in addition, the essentially complete combustion of carbon monoxide produced thereby, within the dense phase zone of the regenerator. A partition in the regenerator divides the lower dense phase zone operating at high temperatures from the upper dilute phase zone which may be cooled, for instance, by boiler tubes, water sprays and the like. The partition contains one or more rough separation catalyst knock-out means such as cyclone separators whereby hot catalyst particles are separated from the rising combusted gases and returned to the dense phase regeneration zone. In one embodiment, the regeneration vessel is elongated to facilitate recovery of most of the extra heat produced by complete carbon monoxide combustion by the catalyst particles returning to the dense phase zone.