油气管道波动压力的雨流计数与分析

Rain-flow counting analysis of the fluctuation pressure for oil & gas pipelines

压力波动严重威胁管道的安全运行,因此,采用雨流计数法对国内5条油气管道的运行压力波动历程进行循环统计。通过压力循环数量和波动幅值等参数的描述和分析,讨论了不同类型管道的压力波动特征及其产生原因,提出了针对性解决方案和运行措施。研究表明:在输送介质、服役年限及外部运行工况等因素的影响下,不同管道的压力循环在数量、压力比和波动幅值等方面存在差异:新建管道压力波动循环次数相对较多,幅度较大;输油管道和输气管道平稳运行期间的压力波动差异较大,输气管道的小幅波动明显多于输油管道,表现为应力腐蚀风险相对较大。数据的采集方式对管道压力波动分析的准确性有明显影响,因此给出了3条原则用于指导管道压力数据采集方法的选取。建议采用雨流计数法定期对管道经历的压力进行统计描述,针对其工作状态和压力波动的产生原因,采取相应措施,避免或减少管道的损伤破坏。

Operation safety of pipelines will be seriously threatened by pressure fluctuation.Therefore,the cyclic statistics about the fluctuation course of operation pressure for 5 inland oil & gas pipelines have been done by using the rain-flow counting method.The cycle number and amplitude of pressure fluctuations are analyzed.And the characteristics and causes of pressure fluctuations for the different type of pipes are also discussed.The authors present specific solutions and operational measures in the paper.Results show that the influences of transport medium,service life and external operating conditions are different for different pipelines,so the number,pressure ratio and fluctuation amplitude of pressure cycles are all different.For example,for newly-constructed pipeline,the cycle numbers of pressure fluctuation are relatively more with larger fluctuation amplitude.And the pressure fluctuations of oil/gas pipelines are quite different during smooth operation.The minor fluctuation in gas pipeline is obviously more than that of oil pipeline.So the risk of stress corrosion is higher.Because of the differences of various data collection methods,a big impact on the analysis accuracy of the pipeline pressure fluctuation will occur.Under this case,3 principles to select the process of data collection methods are needed to be adopted.Suggestion to adopt the rain-flow counting method to conduct a regular statistical description to the pressures that pipeline has been subject to is presented so as to take measures to reduce damages to the pipeline based on the running conditions and fluctuation causes of pipeline.