考虑设备跌落的天然气计量站失效后果计算方法

Study on calculation method of failure consequence for metering station of natural gas considering equipment drop

天然气计量站阀门多且检定流程中频繁使用桁车,常规天然气站场的失效后果计算方法难以评估由此带来的影响及后果。为此,在API 581标准基础上,考虑阀门截断作用对机械损伤事故的影响,选取管段组储气量为最大天然气泄漏量,并以动量定理为依据,研究了桁车失效所引发的设备跌落事故,建立了潜在影响面积计算模型;将影响面积内损伤的管段及设备、泄漏的天然气、伤亡的人员等折算为经济损失,形成了考虑设备跌落的天然气计量站失效后果计算方法;将该方法应用于某天然气计量站。研究结果表明:设备跌落事故损失金额为机械损伤事故的3倍;当考虑设备跌落事故时,管段风险等级由低级上升为中低级。研究结果可为天然气计量站失效后果评价提供理论支撑。

There are many valves in the metering station of natural gas,and the truss cars are frequently used in the verification process,but the influence and consequence brought by these are difficult to evaluate by using the calculation methods of failure consequence for the conventional stations of natural gas.Therefore,on the basis of API 581 standard,the gas storage amount of the pipeline section group was selected as the maximum leakage amount of natural gas with considering the effect of valve blocking on the mechanical damage accidents.According to the momentum theorem,the accident of equipment drop caused by the truss car failure was studied,and a calculation model of potential impact area was established.A calculation method of failure consequence for the metering station of natural gas considering the equipment drop was formed by converting the damaged pipeline section and equipments,leaked natural gas and casualty in the impact area into the economic losses,and this method was applied in a certain metering station of natural gas.The results showed that the loss amount of equipment drop accident was three times that of the mechanical damage accident,and the risk grade of pipeline section increased from low level to middle and low level when considering the equipment drop accident.The results can provide the theoretical support to the evaluation of failure consequence for the metering station of natural gas.