城市聚乙烯燃气管道漏气案例统计与原因分析

Statistics and Cause Analysis of Gas Leakage in Urban Polyethylene Gas Pipelines

目的 分析影响聚乙烯燃气管道漏气的薄弱部位及原因,为建立聚乙烯燃气管道安全服役评价方法可行性分析提供实际数据支撑。方法 收集、归纳某城市聚乙烯燃气管道实际应用中的290例漏气案例,从失效薄弱部位、服役年限、月份等多方面进行统计分析,并讨论聚乙烯燃气管道发生漏气的主要原因。结果 PE燃气管道安全服役的钢塑转换、套袖、焊接位置等连接位置是聚乙烯燃气管道服役的薄弱部位,服役年限与漏气案例比例成正比,且各部位的敏感月份相差较大。影响管道服役的主要因素是环境/应力长期耦合作用和外力突发作用。结论 土壤环境中存在的有机酸介质会加速管道老化,特别是对于施工等带来的固有薄弱缺陷、外界因素带来的表面损伤、应力集中等,在土壤服役环境中化学介质、温度、运行压力的耦合作用下,管道性能大大下降,产生漏气事故,给安全运行带来极大威胁。

The work aims to analyze the weak parts and causes that affect the gas leakage of polyethylene gas pipelines and provide practical data support for the feasibility analysis of the evaluation method for safe service of polyethylene gas pipelines.290 cases of gas leakage in the practical application of polyethylene gas pipelines in Beijing were collected and summarized to make statistical analysis from the aspects of failed and weak parts,service years,months,etc.,and discuss the main causes for gas leakage of polyethylene gas pipelines.The steel-plastic conversion sites,sleeves,welding positions and other connection positions of PE gas pipelines in safe service were the weak parts of PE gas pipelines in service.The service life was proportional to the proportion of gas leakage cases,and the sensitive months of each part were quite different.Through analysis,the main factors affecting pipeline service were determined as the long-term coupling effect of environment/stress and the sudden effect of external force.The organic acid medium existing in the soil environment will accelerate the aging of the pipelines,especially for the inherent weak defects caused by construction,surface damage caused by external factors,stress concentration,etc.Under the coupling action of chemical medium,temperature and operating pressure in the soil service environment,the performance of the pipelines is greatly reduced,resulting in gas leakage accidents,which poses a great threat to safe operation.