Method and system for regenerating fluidizable catalyst particles

A method for regenerating a crystalline zeolite hydrocarbon conversion catalyst which comprises mixing a crystalline zeolite containing hydrocarbon conversion catalyst deactivated with carbonaceous deposits with sufficient hot regenerated catalyst to provide a mix temperature of at least 1175.degree. F., passing the catalyst mixture thus formed suspended in oxygen containing regeneration gases upwardly under coke burning conditions through a first riser regeneration zone discharging radially into the lower portion of an upwardly flowing more dense fluid bed of catalyst particles, passing additional oxygen containing regeneration gases into the lower portion of said dense fluid bed of catalyst below said radial discharge in an amount sufficient to carry the catalyst as a suspension upwardly as a more dispersed phase of catalyst particles undergoing regeneration into a catalyst separating and collecting zone, raising by combustion the temperature of the catalyst mixture passing through said dense catalyst phase and said dilute catalyst phase to at least 1350.degree. F., and recycling hot regenerated catalyst separated from said dispersed catalyst phase directly to the first riser regeneration zone and to a hydrocarbon conversion zone.

In a process for regenerating a coke deactivated crystalline zeolite hydrocarbon conversion catalyst at a temperature above 1175.degree. F. in an upflowing catalyst suspension comprising a dense phase of catalyst particles superimposed by a more dilute phase of catalyst particles thereabove so as to burn carbon monoxide and recover from said dispersed phase regenerated catalyst at an elevated temperature of at least 1350.degree. F., the improvement which comprises,

• mixing regenerated catalyst particles recovered from said dilute catalyst phase at a temperature of at least 1350.degree. F. with coke deactivated catalyst particles in an amount providing a mix temperature of at least 1175.degree. F., adding oxygen containing regeneration gas to said mixture of regenerated and coke deactivated catalyst particles sufficient to form a suspension thereafter passed through an elongated confined zone under coke burning conditions and discharging the suspension thus formed radially into the lower portion of said upflowing dense phase of catalyst particles.

In a process for regenerating a coke deactivated crystalline zeolite hydrocarbon conversion catalyst at a temperature about 1175.degree. F. in an upflowing catalyst regeneration operation comprising a relatively large dense phase of catalyst particles in a lower portion of a regeneration zone in open communication with an upwardly flowing dispersed catalyst phase section of substantially smaller diameter, and recovering regenerated catalyst particles from the upper end of said dispersed catalyst phase, the improvement which comprises,

• mixing hot regenerated catalyst particles obtained from said dispersed catalyst phase with coke deactivated catalyst particles to form a mix temperature of at least 1175.degree. F., passing the mixture thus formed with sufficient oxygen containing gas to initiate combustion of coke on said deactivated catalyst during transfer through a zone of smaller diameter than said dense phase of catalyst, discharging the suspension radially into the lower portion of said dense phase of catalyst for flow upwardly therethrough into said upwardly flowing dispersed catalyst phase thereabove, and
• providing sufficient oxygen containing combustion supporting gas in said dense and dispersed catalyst phases to effect combustion of coke and CO thereby heating said dispersed phase catalyst particles to an elevated temperature of at least 1350.degree. F.

In a process for regenerating a coke deactivated crystalline zeolite hydrocarbon conversion catalyst at an elevated temperature in an upflowing catalyst regeneration zone comprising a relatively large diameter dense fluid bed of catalyst in a lower portion thereof, said regeneration zone diverging into an upwardly extending smaller diameter elongated contact zone wherein coke and carbon monoxide are burned with oxygen containing gas to remove deactivating coke deposits and heat the catalysts to an elevated temperature of at least about 1350.degree. F., the improved method of operation for reducing residual coke on regenerated catalyst below 0.05 weight percent and carbon monoxide in the combustion flue gases less than 0.15 mol percent which comprises,

• mixing coke deactivated crystalline zeolite hydrocarbon conversion catalyst with sufficient hot regenerated catalyst recovered from the upper end of said elongated dispersed phase contact zone at a temperature of at least 1350.degree. F. to form a mixed catalyst temperature of at least 1175.degree. F., contacting the mixed catalyst thus formed with oxygen containing regeneration gas in an elongated catalyst suspension transfer zone under coke burning conditions and discharging the suspension thus provided at an elevated temperature radially into the lower portion of said large diameter dense fluid bed of catalyst.