压气站压缩机出口管道振动测试与安全评定

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

【目的】服役工况下管道振动的安全监测已逐步纳入行业标准化管理体系,压缩机是天然气管道系统的关键设备之一,其出口管道一旦发生明显振动,将会增加整个管道系统的运维风险。【方法】以西气东输管道某压气站压缩机的出口管道为例,通过对出口管道进行振动测试,探究了管道振动发生的规律,深入分析了管道振动的空间轨迹、振动周期以及振动位移等,进而建立了管道振动应力分析有限元模型。【结果】将有限元模型计算结果与压气站现场应力检测结果进行对比,得到计算结果的最大误差为17.5%,验证了新建模型的准确性,并分析了误差产生的原因;基于所建有限元模型,对管道振动引起的x、y、z方向附加应力与分布情况进行了研究,发现y方向振动幅值较大、z方向承受较大的应力,并对振动状态下的管道进行了安全评定。基于管道振动应力分析与安全评定结果,依据管材的许用应力进一步计算了管道在y、z方向的临界振动位移分别为4.4 mm、6.6 mm,并给出了定期开展管道振动在线监测的建议。【结论】采用现场测试与有限元模拟相结合的方法对天然气管道压气站压缩机振动进行分析,厘清了管道振动的规律,并得出了需重点关注风险相对较高的y、z方向的临界振动位移,为天然气管道的风险控制与安全运行提供了参考。

[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 the y and z 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.