Fluid catalytic cracking of hydrocarbons with integrated apparatus for separating and stripping catalyst

摘要

Effective utilization of stripping medium in a process for the fluidized catalytic cracking of a hydrocarbon feedstock is achieved by: (a) passing a hydrocarbon feedstock and solid catalyst particles into a riser conversion zone comprising a conduit (12) to produce a mixture of solid particles and gaseous fluids; (b) passing said mixture of said catalyst particles and gaseous fluids into a separation vessel (11) through said conduit (12) wherein said conduit (12) occupies a central portion of said separation vessel (11) and said separation vessel (11) is located within a reactor vessel (10); (c) tangentially discharging said mixture from said conduit through a discharge opening (16) into said separation vessel (11); (d) passing catalyst particles derived from the mixture into a first catalyst bed (17) located in a lower portion of said separation vessel (11) and contacting said catalyst particles with a first stripping gas in said first bed (17); (e) passing said catalyst particles from said first bed (17) into a second bed (28) located below said first catalyst bed (17), contacting said catalyst particles with a second stripping gas and passing said second stripping gas into said first catalyst bed (17) to supply a portion of said first stripping gas; (f) passing said catalyst particles from said second bed (28) to a stripping zone (30), contacting said particles with a third stripping gas in said stripping zone (30) and passing said third stripping gas into said second catalyst bed (28) to supply at least a portion of said second stripping gas; (g) passing a purge medium (through nozzle 37) into an upper portion of said reactor vessel (10); (h) passing at least a portion of said purge medium through a plurality of restricted openings (40) arranged circumferentially around the outside of said separation vessel (11) at the bottom of said first catalyst bed (17) to supply a portion of said first strippping gas; (i) recovering stripping catalyst particles (through conduit 15) from said stripping zone (30); and, (j) collecting gaseous fluids including said first stripping gas and catalyst from an upper portion of said separation vessel (11) into an outlet (20) and withdrawing gaseous fluids from said separation vessel (11) for recovery.