天然气管道系统目标供气可靠度计算方法

Calculation method for target reliability of natural gas pipeline systems

【目的】天然气管道系统是由众多单元组成的大型、复杂及开放系统,确保安全可靠运行显得尤为重要。随着管道系统可靠性研究的不断深入,系统可靠性指标体系逐渐完善,但尚缺乏有效的系统目标可靠度计算方法,严重制约了天然气管道系统可靠性评价方法的工程实际应用。【方法】提出了一种基于单元可接受风险的天然气管道系统目标供气可靠度计算方法,其包括单元目标可靠度与系统目标供气可靠度两个部分:根据风险可接受准则与风险后果计算方法,构建了基于社会风险与个人风险的管道单元目标可靠度确定模型;考虑天然气管道系统关键单元具有随机失效、气源与用户需求随机波动的特性,构建了基于蒙特卡洛模拟的供气可靠度评价方法,并结合单元目标可靠度计算结果,确定天然气管道系统的目标供气可靠度。【结果】将新建的计算方法应用于中国某天然气管道系统,得到该系统目标供气可靠度为0.999383,将其与基于历史数据统计方法得到的实际供气可靠度0.999404进行对比,评估得出该天然气管道系统可靠度高于目标供气可靠度,能够安全、高效地完成管输任务。【结论】通过实例应用验证了新建计算方法应用于天然气管道系统目标供气可靠度评价的可行性,为后续天然气管道系统可靠性提升与优化研究奠定了技术基础。

[Objective]The natural gas pipelines are large-scale,intricate,and open systems composed of multiple units,with a specialized focus on ensuring safe and reliable operation.Intensive research on pipeline system reliability has been conducted,gradually improving the system reliability index system and evaluation methodology.Nonetheless,the efficient determination method is still absent,having a significant impact on the practical engineering applications of the established reliability evaluation methods for natural gas pipeline systems.[Methods]This paper introduces an approach to determine the target gas supply reliability of natural gas pipeline systems by assessing acceptable risks within their units.The methodology encompasses two key aspects:unit target reliability and system target gas supply reliability.To achieve this,a model for determining the target reliability of pipeline units has been constructed,incorporating both social and individual risks based on risk acceptability criteria and risk consequence calculation methods.Additionally,an evaluation method for gas supply reliability,utilizing a Monte Carlo simulation approach,has been developed.This method takes into account the random failures in crucial units of natural gas pipeline systems and the random fluctuations in gas sources and users'demands.By integrating these evaluation outcomes with the results of unit target reliability calculations,the target gas supply reliability of natural gas pipeline systems can be determined.[Results]The proposed determination approach was applied to a natural gas pipeline system in China,yielding a target gas supply reliability of 0.999383.By comparing it with the actual reliability of gas supply recorded at 0.999404 through the statistics method on historical data,the evaluation demonstrated that this natural gas pipeline system surpassed the target gas supply reliability,indicating its capability to ensure safe and efficient pipeline transmission.[Conclusion]The viability of the proposed determination methodology in evaluating the target gas supply reliability of natural gas pipeline systems has been verified through an application case.The study findings establish a technical groundwork for future studies focused on reliability improvement and optimization for natural gas pipeline systems.