Troubleshooting Tips

Possible Causes of Excessive Catalyst Loss

  1. Inability of the cyclone diplegs to discharge the collected catalyst
  2. Flapper plates on the tickle valves have either fallen off or worse, partially closed
  3. Coke, refractory materials or wet catalyst has partially restricted in the cyclone dustbowls and/or diplegs
  4. Catalyst bed level underneath trickle valves is not uniformly fluidized
  5. Mechanical damage to the air distributor or the stripping steam distributor
  6. Holes in the cyclones, cyclone crossover and/or plenum
  7. Excessive catalyst attrition caused by:
  • Steam to the torch nozzles
  • Blast steam into the riser/J-bend
  • Partially plug nozzles in the steam distributor
  • Very high cyclone velocities
  • Very high velocities in the air distributor
  • Missing restriction orifices in the purge taps and/or aeration nozzles
  • Soft fresh catalyst

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