Study On Vibration Safety Evaluation And Control Of Gas Pipeline In Station

The station is the "heart" of long-distance transportation of oil and gas resources,which plays a vital role in the continuous and efficient transportation of pipelines,and is of great significance to China’s energy security strategy.Usually,the station is equipped with large-scale rotating equipment,such as compressors,centrifugal pumps and so on,which may easily leads to the vibration problem of pipelines connected with them.The vibration may cause fatigue and fracture failure of pipeline,or even leakage explosion.The consequences are unimaginable.Therefore,the problem of the station pipeline vibration has always been the focus of domestic and foreign scholars and pipeline operators.This paper aims at the control of pipeline vibration in the station and the vibration of pipeline in a gas transmission station is systematically and thoroughly studied,starting from the vibration mechanism of pipeline.Firstly,taking the simple basic structure of the pipeline as the breakthrough point,the paper uses the parametric language APDL in the large finite element software ANSYS to compile the numerical simulation model of the vibration of the common "Z" and "U" type elbow structures in the station yard.The influence of the pipe size and elbow structural parameters on the natural frequency of the pipeline is analyzed,which provides a reference and idea for the study of complex pipeline vibration problems.The natural frequencies and vibration modes of complex pipeline system in different order is obtained by establishing a non-linear finite element model of complex pipeline system in a field gas transmission station.The natural frequencies of gas column in complex pipeline system are calculated by classical transfer matrix analysis method.Through comparing with the excitation frequencies,the effective judgment of mechanical resonance and gas column resonance of complex pipeline system is realized.Then,based on the finite element theory,the dynamic response of the compressor outlet pipeline system under the action of pressure pulsation is analyzed.The nodal displacement control method is used to screen the key nodes of the complex pipeline structure and the response regularity of vibration parameters such as acceleration,velocity and displacement of these key nodes are analyzed.The influence of the vibration displacement of compressor block on the vibration of pipeline system is discussed through comparative analysis.Based on the theory of vibration harmonic response analysis,the peak frequency and peak displacement of forced vibration of the pipeline system are calculated,which provides a theoretical basis for the vibration control of pipeline.Finally,based on the Purdue Compressor Association Pipeline Vibration Control Standard,the safety evaluation of the pipeline structure is carried out.The optimum spring stiffness value at the key nodes to effectively weaken and control the vibration of the pipeline system is determined by modal analysis and dynamic response analysis of the pipeline system several times,which provides an important decision basis for the vibration reduction measures at site.