降雨对可燃性气体排放管网的影响及应对措施

Impact of rainfall on inflammable gas vent pipeline and countermeasures

可燃性气体排放管网在降雨后会产生温度及压力骤降现象,工程实践中通常采用补气方式防止排放管网出现负压工况,但补气速率的计算方法较为复杂。为此,以补充氮气为例,通过Ansys Fluent建立管道传热模型,分别研究了补气过程中,管径、初始排放温度、补气速率、管道压力之间的变化规律,采用试差法拟合了补气速率计算公式,并通过Fluent模拟计算验证了该公式具有一定精确度。研究表明,氮气补充速率是管径和初始排放温度的函数,排放温度越高,管径越大,则氮气补充速率越大;在给定的补气速率下,管网压力变化规律为先下降后上升。基于Fluent数值模拟,得出了补气速率计算公式,为可燃性气体排放管网的安全设计和运行提供了高效、便捷、准确的计算方法,提高了工作效率。

There is a sharp pressure and temperature drop of inflammable gas vent pipelines after rainfall. Additional gas is always applied to prevent the negative pressure in the vent pipeline in project practice. Whereas, the calculation of gas addition rate is very complicated. A pipeline heat transfer model is established by Ansys Fluent with nitrogen as additional gas to study the variation laws of pipeline diameter, initial venting temperature, gas addition rate and pipeline pressure in gas addition process. The equation for calculation of gas addition rate is fitted by trial-and-error method, the accuracy of the equation is testified by Fluent simula- tion calculation. The study shows that the nitrogen gas addition rate is the function of pipeline diameter and in- itial venting temperature. With higher venting temperature and larger pipeline diameter, the nitrogen gas addi- tion rate is greater. At a given gas addition rate, the pressure of pipeline first falls down and then goes up. The equation for calculation of gas addition rate developed based upon Fluent numerical simulation has provid- ed a high-efficiency, easy and accurate calculation method for the safety design and operation of inflammable gas vent pipelines.