US 5,288,397 AGranted

Baffled FCC regeneration process and apparatus

AssigneeMobil Oil Corporation

InventorsCatherine L. Markham, Gregory P. Muldowney

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Abstract

A process and apparatus for dense phase, at least partially co-current, fluidized bed regeneration of FCC catalyst are disclosed. Catalyst regeneration occurs in a dense phase fluidized bed, with catalyst flowing laterally from a spent catalyst inlet to a regenerated catalyst outlet. Regeneration air flows up through the dense bed into a dilute phase region defined at the base by the dense phase bed and at the top by a horizontal baffle. The plate has openings or baffles forcing the dilute phase, consisting of entrained catalyst and flue gas, to flow horizontally in the same direction as the lateral flow of catalyst in the dense bed. Concurrent flow of at least the dilute phase material and the dense bed material improves regeneration and can reduce NOx emissions.

Claims18

Dependent claims

A process for the catalytic cracking of a hydrocarbon feed to lighter products comprising:

a. cracking said feed by contacting said feed with a supply of hot, regenerated cracking catalyst in a fluidized catalytic cracking (FCC) reactor means operating at catalytic cracking conditions to produce a mixture of cracked products and spent cracking catalyst containing coke and charging said mixture to a separation means;
b. separating said mixture of cracked products and spent cracking catalyst containing coke in said separation means to produce a cracked product vapor phase which is charged to a fractionation means and a spent catalyst phase which is charged to a catalyst stripping means;
c. stripping said spent catalyst in said stripping means to produce a stripped catalyst phase containing coke and charging said stripped catalyst to a regeneration means having a spent catalyst inlet and a regenerated catalyst outlet;
d. charging to said inlet of said dense phase fluidized bed within said regeneration means said stripped catalyst and regenerating said spent catalyst by contact with oxygen or an oxygen-containing gas at dense phase fluidized bed catalyst regeneration conditions, and wherein there is:
horizontal flow of catalyst from said spent catalyst inlet to a regenerated catalyst outlet, and
vertical flow of regeneration gas from a lower portion of said bed to a dilute phase region above said dense phase bed,
to produce at least partially regenerated catalyst in said dense phase fluidized bed which is withdrawn from said dense phase fluidized bed via said catalyst outlet and flue gas with entrained catalyst which is discharged up from said dense phase fluidized bed into a dilute phase region above said dense phase fluidized bed;
e. horizontally transporting, beneath a horizontal baffle means, at least a majority of said dilute phase, comprising flue gas and entrained catalyst, from said bubbling dense phase bed spent catalyst inlet toward said regenerated catalyst outlet.

5 more elements

A process for the catalytic cracking of a nitrogen containing hydrocarbon feed to lighter products comprising:

a. cracking said feed by contacting said feed with a supply of hot, regenerated cracking catalyst in a fluidized catalytic cracking (FCC) reactor means operating at catalytic cracking conditions to produce a mixture of cracked products and spent cracking catalyst containing coke and nitrogen compounds and charging said mixture to a separation means;
b. separating said mixture of cracked products and spent cracking catalyst containing coke and nitrogen compounds in said separation means to produce a cracked product vapor phase which is charged to a fractionation means and a spent catalyst phase which is charged to a catalyst stripping means;
c. stripping said spent catalyst in said stripping means to produce a stripped catalyst phase containing coke and nitrogen compounds and charging said stripped catalyst to a regeneration means having a spent catalyst inlet and a regenerated catalyst outlet;
d. partially regenerating said spent catalyst in a bubbling dense bed by contact with oxygen or an oxygen-containing gas at dense phase fluidized bed catalyst regeneration conditions sufficient to remove at least 80% of the coke on spent catalyst and produce at least partially regenerated catalyst and flue gas containing oxygen and carbon monoxide gas, and wherein catalyst flows horizontally from said spent catalyst inlet to a spent catalyst outlet and regeneration gas flow is up from a lower portion of said dense bed to a top portion of said dense bed to produce a vertically discharged flue gas comprising entrained catalyst and at least 1.0 mole oxygen and at least 5.0 mole % CO;
e. confining at least a majority of said vertically discharged flue gas within a horizontal baffle no more than 5 feet above the surface of said dense bed and diverting said confined flue gas so that flue gas and entrained catalyst flow is generally concurrent with catalyst flow in said dense bed and afterburning said confined flue gas to produce an increase in temperature of at least 10 F within said confined space and produce a dilute phase product comprising a flue gas with a reduced CO content and entrained, heated, regenerated catalyst and discharging at least 50 volume % of said confined flue gas near said regenerated catalyst outlet;
f. cyclonically separating in cyclone separators having inlet horns within a dilute phase region above said baffle entrained catalyst from flue gas to produce a flue gas stream with a reduced NO.sub.x content as compared to the NO.sub.x content of the flue gas in the absence of said horizontal baffle which is removed from said regenerator and recovered entrained catalyst which is discharged via cyclone diplegs to said dense bed;
and
g. recovering from said regenerated catalyst outlet within said dense bed regenerated catalyst for use in said cracking reactor.

5 more elements

Dependencies are inferred from the claim text.