Situation: North America FCC unit experienced above-normal catalyst losses. In addition to increasing catalyst cost, the increased amount of catalyst in the flue gas accelerated erosion in the HP Steam Generator Coil. New ‘upgraded’ cyclones were installed, but the design modification did not improve the issue.
Action Taken: Becht team of SMEs assessed the situation and found:
- Overloading/flooding of cyclones due to insufficient transport disengaging height (TDH) in the Regenerator,
- Air maldistribution (exacerbates cyclone loading concerns and contributes to afterburn),
- Cyclone geometry could be improved.
Results: Becht determined there was no easy fix
- Long Term – Need to increase regenerator size and continue evaluation of oxygen enrichment to reduce entrained solids,
- Short Term – run unit at max regen pressure possible to keep superficial velocity down and suggested design changes.
The multidiscipline Becht team (Process, Corrosion/Materials, and Mechanical) determined there was no easy fix (Regenerator needed to be larger) but developed long term and short term solutions that would resolve the issue in manners that would require minimal capital cost and unit down time.Contact