输气管道泄漏后截断阀压降速率计算分析

输气管道现存的截断阀压降速率设定值存在着一定的不确定性,在某些大管径管道泄漏时可能无法发挥应有的自关断功能。通过仿真软件建立输气管道泄漏模拟模型,模拟计算出了输气管道5种初始工况在不同管径、不同泄漏孔径下,泄漏点下游阀室截断阀压降速率与持续时间的变化关系以及导致阀门自关断的泄漏孔径数值。对比各种工况结果可知:泄漏孔径越大,截断阀越容易实现自关断功能;当泄漏孔径小于300 mm时,现有的大管径管道截断阀压降速率设定值几乎不会引起截断阀自关断;在高压且高输量情况下发生泄漏时,截断阀更容易实现自关断功能。建议结合输气管道每个管段的物理位置及实际运行参数,设置线路截断阀压降速率值,有针对性地确保管道泄漏后截断阀能够实现自关断。

Calculation and Analysis of Pressure Drop Rate of Block Valve after Leakage of Gas Transmission Pipeline

The existing block valve pressure drop rate set value of gas transmission pipeline has a certain degree of uncertainty. When leakage occurs to some pipeline with large diameter,it may not play its self shut-down function. Based on the simulation software,the simulation model of gas transmission pipeline leakage is established to simulate and calculate the relationship between the block valve pressure drop rate of the valve room downstream from the leakage location and duration time and the leakage aperture value leading to self shut-down of valve of five initial conditions of gas pipeline under different pipeline diameters and leakage apertures. Through comparing all kinds of conditions,it is found that the larger the leakage aperture is,the easier the self shut-down function of block valve realizes. When the leakage aperture is less than 300 mm, the existing pressure drop rate of large-diameter pipeline block valve will hardly cause the self shut-down of block. In the case of high pressure and high throughout,the block valve is more likely to achieve self shut-down function when leakage occurs. It is suggested to set the block valve pressure drop rate of the pipeline with large diameter combining with the physical position and actual operation parameters of each section of the pipeline,thus ensuring that the block valve can realize self shut-down after the leakage of pipeline.