Abstract: Disclosed is an improved regeneration process and system for the regeneration of a spent FCC catalyst in a regenerator without vertical partitions by introducing different fluidization gas streams to different regions of a dense phase catalyst zone at the lower end of the regenerator such as a high velocity central region and a low velocity annular zone are formed, positioned below a common dilute catalyst phase.

Abstract: A regenerator in a FCC unit, with the reactor elevated above the regenerator and a side entry spent catalyst introduction to the regenerator, is modified by installing a spent catalyst distribution apparatus along a central vertical axis of the regenerator to radially discharge the spent catalyst and 10-50 percent of the regeneration air into the dense phase of the catalyst. The existing compressor may be used to supply the regeneration air to the spent catalyst distributor. The remaining 50-90 percent of the regeneration air is supplied to the air distribution grid. The retrofit improves spent catalyst distribution and mixing in the regenerator to avoid dilute phase CO combustion or afterburning in the offgas.