Fluidized process for improved stripping and/or cooling of particulate spent solids, and reduction of sulfur oxide emissions

摘要

A fluidized process which comprises contacting a hydrocarbon feedstock with a fluidized particulate solid in a contacting zone wherein carbonaceous deposits accumulate on the solid and the solid becomes spent and wherein the carbonaceous deposits are burned from the spent solid to produce a regenerated solid; removing a stream of the fluidized spent solid and entrained hydrocarbons from the contacting zone; introducing the fluidized spent solid/entrained hydrocarbon stream and a stream of hot regenerated solid into a lower portion of a zone; introducing a stream of a fluid stripping medium, e.g, water and/or steam into the lower portion of the stripping zone to contact the spent solid therein; passing a stream of the spent solid mixed with the stripping medium and the hot regenerated solid upwardly in the stripping zone to an upper portion thereof under dilute phase stripping conditions; separating the spent solid from the hydrocarbons and stripping medium in a separation zone connected to the upper portion of the stripping zone; passing a fluidized stream of separated solid from the separation zone to the regeneration zone wherein said carbonaceous deposits are burned therefrom to produce a regenerated solid for return to the reaction zone; removing a stream containing vaporized separated hydrocarbons and stripping medium from the separation zone; separating the vaporized separated stripping medium from the hydrocarbons; recycling the separated stripping medium to the stripping zone. The process also contemplates introducing the medium into a lower portion of a dilute phase zone to cool the solid.