Raiser tubes for oil refinery cracking process

Catalyst material used in the fluid catalytic cracking (FCC) refinery process converting heavy oils to more valuable products cause intense wear of some critical components of the process. A short operation life of such components may dramatically reduce the cost effectiveness of the operation.

One such component is the raiser tube. The raiser tube returns the regenerated catalyst back to the reactor. Due to the high temperature (> 600 °C) and high catalyst flow rate (~ 40 m/s) intense local erosion takes place especially in the bottom part where turbulence is the strongest.

The utilization of a metal matrix composite (MMC), Ralloy DMMC 20, as an internal cladding was chosen as a solution to the bottom part erosion problem. This material containing 20% by volume CR₃C₂ was Hot Isostatic Pressed on the inside surface of the load-bearing structure. The raiser tube equipped with the P/M bottom has been in operation for 3 years now with no erosion or other wear problem.