Reduced elevation catalyst return line for a fluid catalytic cracking unit

The present invention is an improved regenerated catalyst bend assembly for a fluid catalytic cracking unit. In one embodiment, the regenerated catalyst conduit (200) for fluidly connecting a regenerator standpipe (55) to a reactor riser (1) of a fluid catalytic cracking unit comprises: a) a first bend with a bend radious, R1, and an inlet end and an outlet end; and b) a second bend with a bend radious, R2, and an inlet end and an outlet end; wherein the inlet end of the first bend is physically connected to the outlet end of the regenerator standpipe (55), the outlet end of the first bend is physically connected to the inlet end of the second bend, the outlet end of the second bend is physically connected to the inlet end of the reactor riser (1), and R1 is not equal to R2. I another embodiment, the conduit comprises a bend with radius, RREL, and a bend inlet end and a bend outlet end; and b) a conduit inlet end and a conduit outlet end; wherein the inlet end of the conduit is physically connected to the outlet end of the regenerator standpipe, and the outlet end of the conduit is physically connected to the reactor riser, wherein the centerline of the reactor riser and the centerline of the outlet end of the conduit are at substantially a 90° angle. The present invention is especially useful in the modification of existing fluid catalytic cracking units to lower the elevation of the outlet of the regenerated catalyst return line assembly, thereby providing needed space to increase the fluid catalytic cracking reactor riser length.