Separation of reacted hydrocarbons and catalyst in fluidized catalytic

Abstract

A specific baffle arrangement within a catalytic reactor improves separation of gaseous hydrocarbon reaction products from catalyst within the reactor vessel of a fluidized catalytic cracker unit. The catalytic reactor vessel includes an outer generally cylindrical shell having a stripping zone arranged at the lower end of the vessel. An inlet riser conduit forming a primary reaction zone extends generally within the shell from the lower end of the vessel to a location near the top of the vessel. A shroud surrounds the upper end of the riser conduit and forms an annular outlet for downwardly discharging a mixtrue of hydrocarbon and catalyst. An annular catalyst disengaging riser baffle for deflecting the mixture from the outlet toward the wall of the vessel is arranged on the outside of the riser conduit below the annular outlet and above the stripping zone. Still further, an annular catalyst disengaging wall baffle is arranged on the inside of the shell for again deflecting the mixture, now mostly catalyst, generally downwardly and toward the stripping zone of the vessel. Preferably, the riser baffle and the wall baffle are arrnaged within the shell such that the baffles in concert with the annular discharge outlet form a partial cyclone separating zone between the baffles to thereby improve the separation of hydrocarbon vapors from the catalyst. This cyclone action promotes early disengagement of hydrocarbon vapor from the catalyst and reduces undesirable catalyst carryover in the vapor to conventional cyclones through which the hydrocarbon products are recovered. At the same time, undesirable secondary cracking reactions in the dilute phase are minimized by lowering the concentration of spent catalyst in the dilute phase.