77
is controlled by the regenerated catalyst slide valve (RCSV), and the opening of this
valve is dependent on the reactor temperature.
4.3 Catalyst Separation
The catalyst along with the gaseous product stream after exiting the riser enters into
the reactor vessel. In modern FCC operations, the reactor serves as a housing for the
cyclones. In the early application of FCC, the reactor vessel provided further bed
cracking, as well as being a device used for additional catalyst separation. There are
cyclones in the regenerator as well. These schemes separate approximately 75–99%
of the catalyst from product vapors [31]. Most cyclone systems operate in two
stages. The combined separation efficiency observed is about 99%. The primary
cyclone doubles as a riser termination device and the primary separator, which separates up to 97% of the catalyst. The dipleg of this cyclone is generally immersed in
the catalyst bed. The secondary cyclone separates the remaining catalyst, and the
hydrocarbon vapors escape to the plenum chamber (Fig. 9).
4.4 Main Fractionation of Products and Gas Recovery
The product vapor exiting the riser is de-superheated and separated in the main
fractionator. The vapors enter the fractionator from the bottom in which they are
condensed and vaporized to achieve the required separation. The reactor vapor is
de-superheated and cooled by several pump around streams. The cooled pump
Fig. 9 Two-stage cyclones [34]
Recent Developments in FCC Process and Catalysts
is controlled by the regenerated catalyst slide valve (RCSV), and the opening of this
valve is dependent on the reactor temperature.
4.3 Catalyst Separation
The catalyst along with the gaseous product stream after exiting the riser enters into
the reactor vessel. In modern FCC operations, the reactor serves as a housing for the
cyclones. In the early application of FCC, the reactor vessel provided further bed
cracking, as well as being a device used for additional catalyst separation. There are
cyclones in the regenerator as well. These schemes separate approximately 75–99%
of the catalyst from product vapors [31]. Most cyclone systems operate in two
stages. The combined separation efficiency observed is about 99%. The primary
cyclone doubles as a riser termination device and the primary separator, which separates up to 97% of the catalyst. The dipleg of this cyclone is generally immersed in
the catalyst bed. The secondary cyclone separates the remaining catalyst, and the
hydrocarbon vapors escape to the plenum chamber (Fig. 9).
4.4 Main Fractionation of Products and Gas Recovery
The product vapor exiting the riser is de-superheated and separated in the main
fractionator. The vapors enter the fractionator from the bottom in which they are
condensed and vaporized to achieve the required separation. The reactor vapor is
de-superheated and cooled by several pump around streams. The cooled pump
Fig. 9 Two-stage cyclones [34]
Recent Developments in FCC Process and Catalysts