FCC process with enclosed vented riser
AssigneeUop LLC
InventorsDavid A. Lomas, Ismail B. Cetinkaya, Steven Niewiedzal, John C. Sheckler, Paul A. Sechrist
Life of this patent
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Abstract
An FCC process uses a highly efficient separation device to remove product from the catalyst so that the reactor vessel receives a low volume of feed hydrocarbons and riser by-products. The separation device encloses an upwardly directed outlet end of a ballistic separation device in low volume disengaging vessel that collects disengaged catalyst from the riser in a dense bed. Immediate contact of the dense bed with a stripping fluid minimizes the amount of hydrocarbons that are carried out of the disengaging vessel into the open volume of the reactor vessel.
Claims15
A process for the fluidized catalytic cracking (FCC) of an FCC feedstock, said process comprising:
- (a) passing said FCC feedstock and regenerated catalyst particles to a reactor riser and transporting said catalyst and feedstock upwardly through said riser thereby converting said feedstock to product vapors and producing spent catalyst particles by the deposition of coke on said regenerated catalyst particles;
- (b) discharging a first mixture of spent catalyst particles and product vapors from a discharge end of said riser upwardly and confining said first mixture into a dilute phase of substantially closed disengaging zone at least partially contained within a dilute phase of a reactor vessel;
- (c) collecting catalyst in said disengaging zone and forming a dense bed of catalyst in said disengaging zone below said discharge end of said riser;
- (d) passing a first stripping fluid stream into said disengaging zone and upwardly through said dense bed and stripping hydrocarbons from said catalyst in said dense bed and passing a first stripping effluent fluid upwardly from said dense bed into said dilute phase of the disengaging zone;
- (e) maintaining said disengaging zone at a lower pressure than said dilute phase of the reactor vessel to restrict the flow of product vapors out of said disengaging zone and maintaining a gas seal between the disengaging zone and said dilute phase of the reactor vessel;
- (f) passing catalyst out of said disengaging zone from the top of said dense bed into a conduit having an inlet opening proximate the top of said the dense bed and in communication with said dilute phase and maintaining a downward catalyst flux through said conduit that will at least partially degas product vapors from catalyst passing through said conduit;
- (g) passing catalyst out of said conduit into a second dense bed through an outlet located below the top of said second dense bed;
- (h) passing catalyst from said second dense bed into a stripping zone and contacting catalyst in said stripping zone with a second stripping fluid stream, passing a second stripping effluent out of said stripping zone and withdrawing a second stripping effluent from said process;
- and
- (i) collecting a product stream comprising product vapors and first stripping effluent from said dilute phase of said disengaging zone and recovering said product stream from said process.
Dependencies are inferred from the claim text.