在役天然气管道的可靠性分析

含缺陷天然气管道的可靠性分析是石油化工行业的一个重要课题。结合可靠性分析的定义,介绍了结构可靠性的基本原理,讨论了腐蚀减薄设备的可靠性模型和可靠度的计算方法。基于可靠性理论,综合考虑了缺陷深度、管道壁厚、管道直径、屈服强度、操作压力等的随机性,确定了天然气管道的可靠度与腐蚀深度的关系。根据一次二阶矩法,建立了腐蚀减薄管道的可靠性模型。根据在役天然气管道的定期检验结果,结合设备可靠性的概念,对于在役天然气管道的减薄的危险部位进行可靠度计算,得出其减薄后的失效可能性。这对该天然气管道的风险评价和延长其检验周期有重要的意义。

Research on the Reliability Analysis of In-service NG Piping

The reliability analysis of natural gas piping containing defects is an important task in the petroleum chemical engineering.Combined with the definition of reliability analysis,the basic principle of the structural reliability is introduced,and then the reliability model and calculation method of the wall thickness reduction device are discussed.The reliability index of NG piping in inverse proportion to the depth defects is determined,with all-round consideration of the uncertainties of the defect depth,the piping wall thickness,the piping diameter,the yield strength,operating pressure etc.The reliablility model of wall thickness reduction piping is established,based on the first-order and second-moment method.According to the results of the periodical inspection of in-service natural gas piping,combined with the reliability concept,the key position of the natural gas piping after wall thickness reduction is calculated through reliability calculation,and then the failure probability is obtained.The failure probability is important for the risk assessment and the prolonged inspection period of the natural gas piping.