Improved FCC unit catalyst stripper

An improved stripper section design is provided for use in fluid catalytic cracking (FCC) units. The stripper section contains means for imparting rotational movement to the FCC cracking catalyst as it traverses the stripping section. In one embodiment the stripper section contains at least one rotation vane that is preferably disposed on the surface of a stripper section tray. The rotation vane provides angular, rotational movement to the cracking catalyst as it traverses the stripper section. Vertical movement is imparted to the cracking catalyst due to gravity and radial movement is imparted to the catalyst due to the slanted nature of the tray. Through the use of the rotation vanes the contact between the catalyst particles and the stripping steam is increased, thereby improving the overall efficiency of the FCC operation.