Conversion of gas oils and residues to light olefins, highoctane gasoline, and distillates using the…
Fluid Catalytic Cracking Process by UOP
Selectively convert gas oils and residue feedstocks into higher value products using the UOP FCC process, the UOP Resid FCC (RFCC) and the UOP PetroFCC process.
UOP’s process uses a side-by-side reactor/regenerator configuration and a patented pre-acceleration zone to condition the regenerated catalyst. Modern Optimix feed distributors inject the feed into the riser, which terminates in a vortex separation system (VSS). A high efficiency stripper then separates the remaining hydrocarbons from the catalyst, which is then reactivated in a combustor-style regenerator. With RxCat technology, a portion of the catalyst that is pre-stripped by the riser termination device can be recycled back to the riser via a standpipe and the MxR chamber.
The reactor zone features a short-contact-time riser, state-of the art riser termination device for quick separation of catalyst and vapor, with high hydrocarbon containment (VSS/VDS technology) and RxCat technology, wherein a portion of the pre-stripped (carbonized) catalyst from the riser termination device is blended with the hotter regenerated catalyst in a proprietary mixing chamber (MxR) for delivery to the riser.
Unlike other approaches to increasing the catalyst-to-oil ratio, this technology does not affect the total heat balance and, therefore, does not increase coke yield. The reactor temperature can be lowered to reduce thermal cracking with no negative impact on conversion, thus improving product selectivity. The ability to vary the carbonized/regenerated catalyst ratio provides considerable flexibility to handle changes in feedstock quality and shortens the time for operating adjustments by enabling rapid switches between gasoline, olefins or distillate operating modes. Since coke yield can be decreased at constant conversion, capacity and reaction severity can be increased, and CO2 emissions reduced. Furthermore, because the catalyst delivered to the regenerator has a higher coke content, it requires less excess oxygen at a given temperature to sustain the same kinetic combustion rate. RxCat technology has been licensed for use in four units, two of which are currently in construction. The first unit to incorporate RxCat technology has been operating successfully since the second quarter of 2005.
The combustor-style regenerator burns coke in a fast-fluidized environment completely to CO2 with very low levels of CO. The circulation of hot catalyst from the upper section to the combustor provides added control over the burn-zone temperature and kinetics and enhances radial mixing. Catalyst coolers can be added to new and existing units to reduce catalyst temperature and increase unit flexibility for commercial operations of feeds up to 6 wt% Conradson carbon. A recent study of eight different combustor-style regenerators and 15 bubbling-bed regenerators clearly demonstrated that at a given excess oxygen level, less NOx is emitted from the combustor-style regenerators than other available technologies.
Products: Light olefins (for alkylation, polymerization, etherification or petrochemicals), LPG, high-octane gasoline, distillates and fuel oils.
Categories: Refining | Tags: Fluid Catalytic Cracking | Comments Off on Fluid Catalytic Cracking Process by UOP