初始温压对超临界/密相CO2管道泄放的影响实验

1.国家管网集团科学技术研究总院分公司;2.中国石油大学(华东)储运与建筑工程学院·山东省油气储运安全重点实验室

CO2管道;泄放实验;浓度扩散;温降

Experiments on the influence of initial temperature and pressure on the relief of supercritical/dense-phase CO2 pipeline
ZHANG Duihong1,CONG Siqi2,HU Qihui2,CHENG Lei1,Liesibieke·TALAFUBIEKE2,HAN Hui2,LI Zhaolan2

1.PipeChina Institute of Science and Technology; 2.College of Pipeline and Civil Engineering, China University of Petroleum (East China)//Shandong Key Laboratory of Oil & Gas Storage and Transportation Safety

CO2 pipeline, relief experiment, concentration diffusion, temperature drop

DOI: 10.6047/j.issn.1000-8241.2024.03.004

备注

【目的】工业CO2管道输送一般维持在超临界/密相高压运行,一旦发生管道泄漏,泄漏口附近区域将产生高浓度CO2,对周围人员、生物等带来严重伤亡威胁。目前针对CO2管道泄漏影响范围与安全距离的定量分析相关研究较为欠缺。【方法】为探究超临界/密相CO2管道泄漏扩散规律,并得到不同CO2暴露浓度下的安全距离,采用自主设计的大型CO2管道泄放扩散实验装置,开展不同压力、温度条件下的CO2管道泄放实验,分析泄放后扩散区域的CO2浓度变化规律及典型体积分数下CO2的影响范围。【结果】在实验压力与温度范围内,近泄放口处CO2的体积分数主要受射流作用影响,在所有实验工况中,距泄放口5m处CO2体积分数最高可达70%,距泄放口10m处CO2体积分数均低于8%。计算得到距离泄放口5m处体积分数大于4%的CO2泄放持续时间最长达到125.6s,随着管内压力的升高,CO2体积分数大于4%的泄放持续时间更久。距离泄放口较远处CO2的体积分数受湍流扩散和环境风速、风向的影响,管内压力在7.5~10.5MPa时,体积分数4%的CO2扩散的最远距离为32m;管内运行温度为20~40℃时,体积分数4%的CO2扩散的最远距离为20m。CO2管道泄放后,扩散区温度也会降低,随着初始压力的升高或管内初始温度的降低,扩散区的温降增大。【结论】管内运行压力越高或管内初始温度越低时,CO2的扩散距离越远,但环境风会影响CO2扩散距离。在工业CO2管道发生泄放后,不仅要根据CO2管道运行状态,还要结合环境风速与风向综合考虑来进行危险区域划定。(图 11表1,参[20]
[Objective] Industrial CO2 pipeline transportation typically operates in a supercritical/dense-phase high-pressure mode. In the event of a pipeline leakage, highly concentrated CO2 will be generated in the vicinity of the leakage port, presenting a significant risk to nearby persons and other creatures. [Methods] Currently, there is a research gap in quantitatively analyzing and evaluating the range of influence and safety distance related to CO2 pipeline leakage. To investigate the leakage and diffusion behavior of supercritical/dense-phase CO2 pipelines and determine safety distances for various CO2 exposure levels, a self-designed, large-scale CO2 pipeline relief and diffusion experimental facility was used to conduct CO2 pipeline relief experiments under varying pressure and temperature conditions, with the aim of examining the change pattern of CO2 concentration in the diffusion zone after relief and the CO2 influence range under typical volume fractions. [Results] Under the experimental pressures and temperatures, the volume fraction of CO2 near the relief outlet was predominantly influenced by jet action. Across all experimental conditions, the volume fraction of CO2 reached up to 70% at a distance of 5 m, while remaining below 8% at 10 m. The relief duration of CO2, with a volume fraction exceeding 4% at a distance of 5 m from the relief outlet, was calculated to be up to 125 s. Moreover, higher operating pressures in the pipe resulted in prolonged relief duration. The volume fraction of CO2 at a distant location from the relief outlet was influenced by turbulent diffusion and ambient wind conditions. For CO2 with a volume fraction of 4%, the maximum diffusion distance was 32 m at pressures ranging from 7.5 MPa to 10.5 MPa and 20 m at operating temperatures ranging from 20 °C to 40 °C. Following the CO2 pipeline relief, the temperature in the diffusion zone decreased, and the temperature drop in the diffusion zone increased with higher initial pressure or lower initial temperature in the pipe. [Conclusion] The diffusion distance of CO2 is influenced by both the operating pressure and the initial temperature in the pipe. Higher operating pressure or lower initial temperature will result in a greater diffusion distance. Additionally, the diffusion distance can also be influenced by ambient wind conditions. After the relief of an industrial CO2 pipeline, the hazardous area must be clearly demarcated, taking into account the operating status of the pipeline as well as a comprehensive evaluation of ambient wind speed and direction. (11 Figures, 1 Table, 20 References)
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