English abstract
Centrifugal compressors are the most prevalent units in any gas processing plant.
Optimizing the efficiency and maximizing the reliability of these machines are of
utmost importance for sustaining feasible plant production. This thesis research
introduces a step-by-step approach to assessing the aerothermodynamic performance
of process centrifugal compressors. Leveraging recent advances in real gas theoretical
principles, the approach relies on the GERG-2008 equation of state for calculating the
gas thermodynamic properties, accommodating complex compositions of up to 21
components. Furthermore, the considered methodology uses the Huntington FourPoint method for evaluating the polytropic head and efficiency of the compressor
section. The accuracy and convergence of the developed algorithm were investigated
after it was developed into a computer program. The developed approach was also
compared with literature records using three comparative approaches: relative error,
linear regression, and paired t-test. The outcomes of these comparisons revealed
unwavering conformity between the obtained results and their counterparts in the
literature. The maximum deviation in thermodynamic properties was 0.5% for isobaric
heat capacity. For polytropic efficiency, the maximum deviation was 0.016%.
Moreover, the proposed methodology was applied on two industrial cases, in which
the developed algorithm was used to diagnose oil ingress and deposit accumulation in
natural gas centrifugal compressors. The proposed methodology proved its robustness
in identifying machine underperformance that otherwise could not be identified as
accurately using the existing practices and maintenance protocols by the local
compressor end-users. The developed algorithm provides a robust solution for the endusers for carrying out instantaneous and highly accurate performance assessments.
