Method and apparatus for improved fluid catalytic riser reactor cracking

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.