超临界/密相CO_(2)管道泄漏压力响应及低温规律实验研究

Experimental study on leakage pressure response and low-temperature law of supercritical/dense phase CO_(2) pipeline

为进一步了解超临界/密相CO_(2)在管道泄漏过程中的压力响应和温度变化,基于自行设计的高压CO_(2)管道泄漏实验装置,探讨压力响应、温降特性和相态变化的相互作用机理,以及低温分布规律。研究结果表明:19 mm口径纯CO_(2)的压降曲线有明显的2个阶段,且密相泄放存在明显的压力平台,N 2会明显提高泄放速率;相同截面上温度呈现“上热下冷”的分布特征,管道轴线方向,泄放端温降相对最严重;从相态变化角度看,超临界CO_(2)泄漏没有明显两相区,但对于密相而言,管道底部的CO_(2)会经历密相、液相、过热液相、气液两相、气相的相态转变过程。研究结果可为管道泄放安全运行以及规避断裂风险等方案设计提供参考。

In order to understand the pressure response and temperature change law of supercritical/dense phase CO_(2) during pipeline leakage,based on the self-designed experimental device for high-pressure CO_(2) pipeline leakage,the interaction mechanism of pressure response,temperature drop characteristics and phase transition was explored,as well as the low-temperature distribution law.The results show that the pressure drop curve of pure CO_(2) under 19 mm diameter has two obvious stages,and there is an obvious pressure platform in the leakage of dense phase,while N 2 will obviously increase the leakage rate.The temperature on the same section presents the distribution characteristics of“upper hot and lower cold”,and the temperature drop at the release end in the pipeline axis direction is the most serious.From the perspective of phase transition,there is no obvious two-phase zone in supercritical CO_(2) leakage,and for the dense phase,the CO_(2) at the bottom of pipeline will undergo the phase transition process of dense phase,liquid phase,superheated liquid phase,gas-liquid two-phase and pure gas phase.The research results can provide reference for the safe operation of pipeline discharge and the avoidance of fracture risk.