Systematics *FCC (6): Linear velocity of the dense and dilute phases in the reactive regeneration system
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Under normal conditions, what are the typical linear velocities of the dense and dilute phases in the reaction settler and regenerator of a catalytic cracking unit?
The linear velocity of the dense phase bed in the reactor is generally 0.3–0.9 m/s； The design linear velocity of the settler should not exceed 0.6–0.6 m/s. The linear velocity of the dense bed layer in the regenerator is generally 0.6–1.2 m/s.
The linear velocity of the dense phase in the regenerator depends mainly on its structural design: if it is a coking drum, operation takes place beneath a fast bed, and the velocity can reach around 1 m/s; for ordinary regenerators, the velocity is around 0.5 to 0.8 m/s. This value can be determined by using the main air flow rate along with calculations based on pressure and temperature
Regenerator dense-phase bubble column linear velocity: 0.15~0.25 m/s; turbulent bed linear velocity: >0.6 m/s; rapid bed linear velocity: 0.9~3 m/s. Lift tube reactor: pre-lift section: 2~4 m/s; linear velocity at the feed nozzle: 4.5~7.5 m/s; outlet of the lift tube: 10~18 m/s