Abstract: One exemplary embodiment can be a fluid catalytic cracking system. The fluid catalytic cracking system can include a reaction zone including a riser having a top and a bottom adapted to receive spent catalyst at a first elevation and regenerated catalyst at a second elevation. Typically, the first elevation is lower than the second elevation. Additionally, the fluid catalytic cracking system can include a gas distributor contained near the bottom of the riser in communication with a hydrocarbon feed.

Abstract: An FCC process producing lower NOx emissions during regeneration by using excess oxygen levels at less than or equal to about 0.5 mol-% and a plenum temperature above about 730° C. (about 1350° F.). The process may further include limiting the Pt content in the catalyst to less than or equal to about 0.5 ppm. NOx emissions, NO to NO2, produced through this process may be equal to or less than 25 ppmv. The process may also include adjusting the metal content of the feedstock for such metals as antimony, nickel, or vanadium. Additional variables for reducing NOx emissions that may be used in conjunction with this process may include increasing the flue gas residence time, injecting NH3 into the flue gas, adding or using NOx-reducing catalysts, increasing stripping of the catalyst, and increasing the catalyst zeolite to matrix ratio.

Abstract: One exemplary embodiment can be a fluid catalytic cracking unit. The fluid catalytic cracking unit can include a first riser, a second riser, and a disengagement zone. The first riser can be adapted to receive a first feed terminating at a first reaction vessel having a first volume. The second riser may be adapted to receive a second feed terminating at a second reaction vessel having a second volume. Generally, the first volume is greater than the second volume. What is more, the disengagement zone can be for receiving a first mixture including at least one catalyst and one or more products from the first reaction vessel, and a second mixture including at least one catalyst and one or more products from the second reaction vessel. Typically, the first mixture is isolated from the second mixture.

Abstract: One exemplary embodiment can be a fluid catalytic cracking system. The fluid catalytic cracking system can include a reaction zone including a riser having a top and a bottom adapted to receive spent catalyst at a first elevation and regenerated catalyst at a second elevation. Typically, the first elevation is lower than the second elevation. Additionally, the fluid catalytic cracking system can include a gas distributor contained near the bottom of the riser in communication with a hydrocarbon feed.

Abstract: An alkylation process in which a recycle stream is cooled by heat exchange with the alkylation reactor effluent is disclosed.