改进作业条件分析法在输气站场安全评价中的应用研究

Application study of improved LEC method in gas transmission station safety assessment

输气站场是天然气输送的关键环节,站内设备繁多,管道密集,输送介质易燃易爆,且输送量大,作业活动存在很大风险。在调研分析输气站场主要危险活动的基础上,采用改进后的作业条件分析方法(LEC)分析了作业活动中发生事故的可能性、频率及后果,提出了改进措施。改进后的LEC法中的事故发生可能性(L)采用事故树(FTA)法进行定量分析,避免了取值的主观性。同时结合输气站场作业管理特点,在作业条件风险分析(LEC)基础上,增加了监控措施补偿系数M,包括危险事件监测措施补偿系数和危险事件控制措施两方面。分析结果表明,改进后的作业条件分析方法能够更加准确合理地评定作业危险等级,还可有效运用于输气站场的持续改进评价过程中。

The paper is aimed at presenting a renovated LEC method with the purpose of enhancing the safety of the natural gas transmission. As is known, it is the key link for the natural gas transmission stations to prevent all kinds of likely hazards, such as gas-fire and gas-explosion, which pushed us to work out the following renovated LEC method. In order to achieve our purpose, we have first of all improved the fault tree of gas fire and explosion through a quantitative analysis so as to overcome the subjectivity of evaluation. Secondly, combined with the characteristics of gas transmission station and based on the traditional LEC method, we have enhanced monitoring measures for compensation coefficient （M） to the LEC method, including the hazardous event monitoring measures compensation coefficient （M1） and hazardous events control measures （M2）. Thirdly, we have worked out the chance probability of hazardous events by using the gas station hazards-identifying and fault-tree analysis in combination with the hazardous event monitoring measures （M1） and hazardous events control measures （M2） by quantifying the probability and criticality. The analysis results show that if monitoring and management measures can be made appropriate, the chance probability of the fire and explosion hazards won＆rsquo;t be high, unless the effects fail to receive enough attention as in the traditional LEC method. Therefore, our renovated method has paid greater attention to the analysis of the potential hazard level and impersonality results, and provides evidence for gas transmission station hazard management. In our improved LEC method, we just used the FTA method for accounting the probability of accidents so as to reduce the value subjectivity. In combination with the gas station operation management characteristics, we have also added the monitoring measures compensation coefficient to the LEC method, including the hazardous event monitoring measures compensation coefficient and hazardous events control measures. The analysis results of ours indicate that our renovated LEC method can offer more accurate and reasonable hazard-level evaluations and make them improved for effective evaluation of such processes.