Updated: Jan 29, 2021
Becht | Engineering Solutions, Plant Services, and Software Tool Provider
A client was operating an Exxon Model IV FCCU (fluid catalytic cracking unit). The main air blower steam turbine driver shaft experienced significant and continual axial movement in the direction of thrust that was approaching trip levels.
The client planned to temporarily replace the air flow from the main air blower to the regenerator using a number of rental compressors (47 proposed). Some compressors were diesel driven, and some were powered by 10 temporary generators.
A Becht team performed a cold eyes review of the installation of the temporary compressors, proposed control strategy, and startup/shutdown and transition procedures of the temporary system. The flow in the temporary air tie-in points to the main air line was high. A mechanical evaluation of these points was conducted to ensure there would be no failure in these areas due to high flow-induced vibration.
Becht’s SMEs provided 24 hours/day virtual support during the operation, including monitoring, suggesting adjustments to the console operators, etc. As a result, the client was able to keep the FCC unit in operation during the transition of the shutdown and restart of the main air blower, as well as for the 40 days it took for the steam turbine driver replacement, with no downtime for the unit, saving upwards of $10MM.