To convert heavy distillates and residues into high-value products, including selective propylene production when required, using the Shell fluid catalytic cracking (FCC) process.
In this process, Shell’s high-performance feed nozzle system feeds hydrocarbons to a short contact-time riser. This design ensures good mixing and rapid vaporization into the hot catalyst stream. Cracking selectivity is enhanced by the feed nozzles and proprietary riser-internals, which reduce catalyst back mixing while reducing overall riser pressure drop.
Riser termination design incorporates reliable close-couple cyclones that provide rapid catalyst/hydrocarbon separation. It minimizes post riser cracking and maximizes desired product yields, with no slurry clean up required. Stripping begins in the staged stripper, equipped with high capacity baffle structure.
A single-stage partial or full-burn regenerator delivers excellent performance at low cost. Proprietary internals are used at the catalyst inlet to disperse catalyst, and the catalyst outlet to provide significant catalyst circulation enhancement. Catalyst coolers can be added for more feedstock flexibility.
Cyclone-systems in the reactor and regenerator use a proprietary design, thus providing reliability, efficiency and robustness. Flue gas cleanup can be incorporated with Shell’s third-stage separator.
Shell Global Solutions FCC technologies are proven reliability champions due to simplicity of components and incorporation of Shell’s extensive operating experience. The latest addition to the Shell Global Solutions FCC technology is the MILOS process (Middle Distillate and Lower Olefins Selective process). With this technology, refiners can produce more diesel with improved quality and more propylene from FCC units. The key element
of MILOS is a separate riser to produce the additional propylene, with its own optimal process conditions, while the existing FCC riser is used for “normal” cracking or for enhanced light cycle oil (LCO) make. This process option has a wide flexibility with respect to products, ranging from the normal product slate to maximized propylene or diesel, which can be achieved through operational measures.
Supplier: Shell Global Solutions International B.V.