The reaction section of an FCC typically operates around 530oC. Cyclones are frequently employed to separate the catalyst from the hydrocarbon vapors, passing up the riser followed by second-stage cyclones for final clean-up. Alternatively, a single stage of high-efficiency cyclones can be used to remove residual catalysts from the gas stream, where a licenser’s proprietary pre-separator has been used to remove the majority of the catalyst.
After the reaction is complete, carbon is deposited onto the surface of the catalyst which is then burnt off in the regenerator to maintain the activity of the catalyst. Regenerators typically operate around 730oC. Most regenerators operate fluid beds, and two stages of cyclones are employed to remove the catalyst – which is elutriated from the fluid bed and returned back into the bed.