Centrifugal Compressor Condition Based Maintenance

Figure 1 – Polytropic efficiency over time of compressor sections.

Figure 2 – % Opening of primary vent valve and primary vent ∆P trend over time.

Location Singapore
ApplicationButyl Production
Compressor TypeCentrifugal compressors – LP + HP
ServiceEthylene compression
Power6650 kW
Disch. Pressure20.5 bara


Define the optimal scope of maintenance for the compressors train through an analytical and data driven approach.

Focus of Analysis

  • Polytropic efficiency depletion trend (as proxy of laby seals health)
  • DGSs buffer pressure increasing trend (as proxy of DGSs health)


CST recommended to skip the Major Overhaul at the upcoming early 2023 shutdown, only replacing the DGSs. Rescheduling the MOH for 2028


Significant Opex saving and shorten the window of the Turnaround thus saving production for 2,000 k$.