Method for spent catalyst treating for fluidized catalytic cracking systems

摘要

A method for increasing the overall efficiency of fluidized catalytic cracking (FCC) with crystalline zeolitic catalysts is disclosed. Separated or spend cracking catalyst after reaction with hydrocarbonaceous material is first stripped and then subjected to an additional period of time in the presence of steam in the dense phase before the catalyst is returned to a regenerator. In a preferred form the spent catalyst after normal steam stripping is subjected to an additional period from 1/2 to 30 minutes at elevated temperature. This time is from 6 to 900 times the reaction time of the catalyst and hydrocarbonaceous mixture in an FCC reactor riser pipe. Such additional steam exposure allows the stripped spent catalyst to react with the steam to produce one or more significant benefits in FCC operations.