Vibrations in a refinery FCC unit led to repeated ducting failures. In addition, the gas traveling through the ducting was a source of excessive noise. Hopper Engineering Associates was retained to mitigate both noise and vibration issues in the system.
Geometry, noise and vibration data was collected in the field. A scale model of the system was constructed and analyzed in a laboratory. Additionally, a quantitative analysis was preformed to identify potential resonances between excitation forces, acoustic frequencies and mechanical/structural frequencies. The excitation forces studied included plant machinery (pumps, compressors, blowers, etc.) and flow induced excitation caused by flow restrictions and obstructions (vortex shedding, broadband turbulent energy, acoustic cavaties, etc.). Modifications were suggested to reduce noise and vibration in the system.