Vibration testing and safety assessment of compressor outlet piping for compressor station

Objective The oil and gas industry has gradually integrated the safety monitoring of piping vibration under service conditions into the standard management system. This is especially true for the outlet piping of compressors, which are critical components in natural gas pipeline systems, since heightened vibration in this section of the piping can increase operational and maintenance risks for the entire pipeline system.

Methods Through vibration testing conducted on the outlet piping of compressors at a compressor station along the West-East Gas Pipeline, this study investigated the piping vibration patterns. It further delved into spatial trajectories, vibration cycles, and displacements related to piping vibration. Subsequently, a finite element model was established to analyze stress during piping vibration.

Results By comparing the calculation results obtained using the finite element model with the measured stress at the compressor station, it was found that the maximum error of the calculation results was 17.5%, demonstrating the accuracy of the devised model. Subsequently, the causes of errors were explored. The investigation of additional stress and its distribution in the x, y, and z directions induced by piping vibration using the finite element model revealed significant vibration amplitudes in the y direction and substantial stress in the z direction. These results were utilized in the safety assessment of the piping under vibration conditions. Based on the stress analysis and safety assessment, the critical vibration displacements of the piping in they andz directions were further calculated to be 4.4 mm and 6.6 mm, respectively, taking into account the allowable stress of the pipes. Furthermore, it is recommended to implement regular online monitoring of piping vibration.

Conclusion This study focused on analyzing compressor vibration at compressor stations along natural gas pipelines utilizing a methodology that integrates field testing and finite element simulations. The research outcomes elucidate the piping vibration patterns and underscore the critical vibration displacements in the y and z directions, indicating comparatively high-risk levels that necessitate more consideration. These results serve as a reference for risk control and operational safety of natural gas pipelines.